TC/Elcon 2013 Charger Troubleshooting and Repair

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TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 06:43

This repair information is for the models with the NXP processor, which seem to be the ones with the 7-pin round connector. Basically, if the charger has a 7-pin round connector, then it has the NXP processor and these repair hints apply.

This information was previously posted to DiyElectriccar.com here:

https://www.diyelectriccar.com/forums/s ... post452281

Coulomb's index

I've decided to put an index here to what I consider to be the more useful posts in this thread. Yes, it's mainly for my own use, but others may find it useful as well. PM me if you find a post you think is worth adding to this index.

Re-assembly notes, including the heaksink clamp removing tool, and Reassembly tips.
Transformer transplant.
Discussion on the reliability of the bridge rectifier, and effect of disconnecting mains under load. More here.
Drill this through if replacing the rectifiers on the high voltage models.
8 kW model photos.
Using jumpers in troubleshooting; more troubleshooting tips.
SOT-23 devices marked "A1t".
"Desaturation" schematic.
PCB with C38 (large capacitor near MOSFETS) removed. Also C2 and C46 small capacitors nearby.
Improving creepage distance between MOSFET leads.
Input relay photos.
The mystery of the faint crackling sound solved.
How NOT to replace the heatsink clamps.
Start of discussion on replacement pre-charge resistors (150Ω 2-3 W near input relay). Continues for several posts.
Measurements possible without taking out the main PCB. Next post has possible repairs without taking out the main PCB.
Replacing the HF transformer.
Q7, Q8 PFC MOSFETs
Cleaned-up control board (daughter board) image (large)


For convenience, some links to revised schematics (in another thread):

DC output section schematic.
Control (daughter) board schematic as four pages.
AC input schematic.

---------------------

WARNING


The DC bus capacitors collapse to around 10 V soon after the input (pre-charge bypass) relay clicks off, but the capacitors in the output section retain a nasty, possibly lethal bite for roughly a minute after turning off the power.

While there is an output relay, its contacts are bypassed with a resistor, which would limit any shock from touching both outputs to a likely non-lethal belt, but it is still dangerous, and you should take precautions.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 06:51

I thought I posted this elsewhere, but I can't find it.

When re-assembling an Elcon/TC charger after having removed the main PCB from the heatsinks, it's important to use a suitable tool to prevent this sort of problem:

Elcon charger MOSFETs 004 sm.jpg
Elcon charger MOSFETs 004 sm.jpg (36.96 KiB) Viewed 260 times
Note how the nearest MOSFET has been twisted, and is likely shorting its leads together.

The best solution seems to be to use a tool to prise the really strong heatsink clamps apart when positioning the clamps on the MOSFETS (also the diodes and bridge). Petrhaps a pair of spoons would do; I found a pair of screwdrivers was not terribly good. I found this pair of pieces of aluminum worked for me:

Elcon external 001 sm.jpg
Elcon external 001 sm.jpg (31.24 KiB) Viewed 260 times
These are actually heat-sinks for diodes from an old welder, but obviously any scraps of metal about the right size would do. You can just squeeze the pieces of metal together to prise the clamps apart, and they are (just barely) not too big to get in the way of other parts of the charger. You may have to trim your scraps to size.

[ Edit: the later models have slightly different clips, so 3 mm aluminium is too thick. So you'll need 2 mm, and aluminium may be too weak, so steel is preferred. ]
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:06

kennybobby;736633 wrote: I think Paul and i were thrown by the Q designation on the pcb and were trying to make them transistors.
Yes, it's strange that half the diodes are designated as Ds, and half as Qs :confused:
I think we have a unit here that resists repair also--replaced numerous chips and bits which were taken out again on powerup. ... But it is disheartening when all that hard work goes up in smoke...
Absolutely. I believe that this one was one where the use of the current limited power supply and the jumpers saved that heart breaking moment. It's so easy to overlook something.

Now a few notes about reassembly. I've noted that you really need to remove both cables (mains input and DC output) to get the PCB out. It turns out it's really helpful at least on reassembly to remove the control cable (to the 7-pin round connector, if supplied) as well. It's a pest to get out, especially to get it completely out, but the following is as far as is needed:

Seven pin unobstruct.jpg
Seven pin unobstruct.jpg (87.55 KiB) Viewed 255 times
It's still plenty hassle to get it to that stage, but that's enough to get the PCB past easily. If you really wanted to get it out completely, you could probably use a jeweller's flat blade screwdriver to release the metal pins in the plastic socket; you can see the seven slots where you can get access to the piece of metal that holds the pins in place. Mark one end of both the ribbon and plastic shroud to make sure it goes back the right way around.

For the 2 kW chargers only, the PFC inductor is so large that it has its own octagonal heatsink:

PFC inductor heatsink.jpg
PFC inductor heatsink.jpg (82.72 KiB) Viewed 255 times
I found this one was still attached to the bottom of the PCB, but had slid away from its original position while still held firmly in place by the thermal paste. I found it well worth taking if off the PCB and placing it on the main chassis. The long threaded rod is actually a very long bolt captured in a slot; it is free to move along this slot. Move it to approximately the right position before attempting to reinstall the PCB.

Speaking of thermal paste, there is a LOT of this stuff in these chargers. If you have a 10 g or 20 g tube of it, it's likely to be a bit short. You might not need as large a tube as I use unless you do a lot of charger repairs, but make sure you have a fair bit available before reassembly.

Large thermal paste.jpg
Large thermal paste.jpg (50.53 KiB) Viewed 255 times
Finally, the high frequency transformer (large yellow cube with gold anodized aluminum metalwork) has four screws holding it in place, and again these screws are free to move in slots in the chassis. Move the screws to approximately the right position before attempting to reinstall the PCB. The Xs indicate where two screws ended up; obviously, they need to be near either end. The arrow shows the direction and rough length of the slots.

Transformer reinstall.jpg
Transformer reinstall.jpg (125.58 KiB) Viewed 255 times
Similar comments apply to the full bridge inductor (next to the 3 position output terminal block). It has one bolt in a slot that should be moved to approximately the right position (nearest the daughter board) before moving the PCB into place. (Two other bolts are inserted from above.) So re-inserting the PCB is a matter of juggling the PCB itself and the 5 or 6 screws (1.5 kW or 2 kW respectively) for the various inductors. Patience is a virtue here.

[ Edit: brass metalwork -> gold anodized aluminum metalwork ]
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:08

Vectrix150V;532793 wrote: I've got a working 156V (13S flooded cells - 180V 11A max) 2Kw unit that I swapped the transformer and inductor from a 2Kw 120V (160V Max) unit - but have run into troubles with trimming the output voltage.
Ooh - a transformer transplant! We've thought about that, but I don't think that's been done before.
(The 160V unit was unrepairable)
Heh. Paul, are you still in "I like the challenge" mode? :eek:
Due to the divider - both transformers produce 180V output.
I guess that's what we'd expect.
I've tried the method here - https://www.diyelectriccar.com/forums/s ... 51100.html BUT no luck - it either runs at 180V or doesn't detect the battery (sigh).

Is it possible to reprogram a 155V 13A lithium curve/program into it? The lead one seems strange - it is doing an absorb or equalisation routine - voltage pulses at end, not what I need (and it doesn't have the BMS control contacts either).
The short answer is yes, we have the technology to to this sort of thing now.
Was a PITA to disassemble and reassemble these things.
Yes, they are a bit of a pain.

Unfortunately, reprogramming them is a different sort of pain. You will need to build two simple interface circuits, and you will need a serial USB dongle and an Arduino board of pretty much any sort. We can send the software you will need, but you'll need to have a bit of a software bent to do this. Having succeeded with the transformer transplant, you certainly have a hardware bent. Are you up for this additional challenge?

I was going to document what we know on the AEVA site once it's settled down (they're going through a painful database translation process at the moment). Maybe I should do it on DIY if you are ready.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:09

I'm doing another repair. Classic burned-up pre-charge resistors. This one also has the bottom half of the bridge shorted (both diodes connected to the negative terminal). This sounds familiar; I wonder if this is a common pattern? When the bridge shorts like that, then the AC input is shorted past the pre-charge resistors, so nothing will get through to turn on the relay, and the pre-charge resistors are guaranteed a crispy demise.

Have others seen this pattern, or is this just one of many ways the input circuitry can fail?

I've noticed that when you disconnect these chargers at the mains end under load, the arc is pretty spectacular. I'm guessing that the energy for that spark/arc comes from the main PFC inductor (not the medium sized common mode chokes; these should have little leakage inductance), and so all this energy has to conduct through the bridge rectifier. They are moderately stout (from memory, 25 A and 1000 V rated; I feel bad replacing them with 800 V units now), but 800 V or 1000 V, they aren't going to last long if they regularly get the mains disconnected under load.

So maybe this is a failure mechanism: people control the charge by taking the power away with a relay, or switch, or just yanking out the power plug because it's time to go drive the EV, and the energy of the PFC inductor goes through the bridge to the arc at the switch/relay/plug and fries whichever half of the bridge needs to conduct to keep the current flowing (I think it might depend on the polarity of the mains at the time; if it happened to be close to a zero crossing, it might fry both halves of the bridge).

Plausible?

I wonder how other chargers handle this? There is a movistor in the Elcons, but it's before the bridge (presumably, to protect the charger from mains transients). Maybe there should be another one after the bridge?
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:13

I have another theory about how the bridge rectifier may be failing. This one is also a bit of a long shot, I think.

It could be when the user *reconnects* the charger, after the main capacitor voltage has decreased significantly, *but before* the 12 V power supply drops out. So the pre-charge resistors are still shorted by the input relay. When the mains is re-applied, the bridge rectifier has to take the full in-rush current of re-charging the main capacitors (which are 2 x 220 uF paralleled for the 1500 W models, or 3 x 220 uF for the 2000/2500 W models). So this takes them from say 40-50 V (still enough to keep the Viper running) to 170 V (120 V mains) or 340 V (240 V mains). Near the peaks of the mains cycles, this inrush current could be quite considerable. Near the zero crossings, the >= 40 V across the bus capacitors will reverse bias the bridge rectifiers, so no inrush current will flow. In between, there will be between nothing and very considerable in-rush currents. So this would introduce an indeterminacy to the problem, suggesting why it hasn't been enough of an issue to have been corrected by now. The indeterminacy / randomness would be exaggerated by the user having to wait such a long time before it is safe to reconnect (it seems to me to be about 30 seconds). People's patience waiting for the charger to stop would naturally be quite variable. Sometimes, the charger is buried in a car, so you can't see the red/green LED, and may not be able to hear the soft "tink" sound of the input relay disconnecting. So then it becomes truly random: "oh hell that has to be long enough... "<<plug>> <<splat>>. Assuming that the bridge rectifier fails shorted (AC input to other AC input), there will be no DC bus voltage, so there will be no 12 V supply, so the mains fuse doesn't blow, and the pre-charge resistors then fry.

A nice corollary of this theory (if indeed it is right), is that there is a possible improvement: use a beefier (higher *current* rating) bridge rectifier. There are 40 A and 45 A versions available in the same style of package (just with metal showing, instead of being all glass passivated). Here is one such:

http://www.newark.com/vishay-general-se ... dp/79R2489

Image

So in summary, the theories about frying the pre-charge resistors are:

  • Overheating. The Viper chip shuts down to save itself, but this opens the input relay, so the full mains current runs through the pre-charge resistors, and they fry.
  • Inductive kickback. Either the main PFC inductor or the common mode choke inductors, or both, cause a large voltage spike that takes out the bridge rectifier, causing a short AC in to other AC in. This drops out the DC bus, hence the 12 V, hence the input relay, and the pre-charge resistors end up across the mains, and they burn up.
  • Premature re-connect. The user reconnects the mains while the DC bus capacitors have discharged a lot, but the Viper is still running, so the input relay is still shorting the pre-charge resistors. The resulting in-rush current overloads the bridge rectifier, which shorts AC in to AC in. As with the inductive kickback, this results in the pre-charge resistors ending up across the mains.
The problems with the pre-charge resistors seems to be exacerbated by the manufacturer's choice of carbon resistors for this role. They have been seen to *reduce* in resistance with excess heat, which of course makes them draw more current. Usually, this is not enough to blow the 20 A input fuses. This can result in enough heat to cause the nearby input relay to crumble to charcoal, as we've seen. Wirewound types would appear to be more suitable in this role.


In all three scenarios, the bridge rectifier may be damaged / shorted. However, in the last two scenarios (my theories), it's the shorting of the bridge rectifier that initiates the problem. So if it is found that the bridge rectifier is commonly not shorted AC in to other AC in, then my theories are disproved. If you have a charger with a shorted bridge rectifier, it is possible to detect this IF the pre-charge resistors have not failed open circuit (which they often do, merely by crumbling apart). With a shorted bridge rectifier, you will essentially read the value of the pre-charge resistors from the line to neutral pins of the mains plug. So if you read around 75 ohms, or really anything from about twenty ohms to about a thousand ohms, then you have a shorted bridge rectifier, and should not plug it in. If the bridge rectifier is good, you should read some megohms in both directions, changing rapidly. If you read infinite resistance immediately both directions, then either the input fuse or something else has opened circuit, and the charger won't work but should be safe enough to plug in and try anyway.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:16

For those working on the higher voltage chargers, another little tip (see photo).

Without this, I found that the little PCB would rise up with the screw, and the screw would not go into the heatsink.

It was a two person job replacing the diode stack, and required the patience of a saint. But I got there in the end.
Attachments
Drill this through sm.jpg
Drill this through sm.jpg (86.26 KiB) Viewed 252 times
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:22

This post from user Ruudi:

Hello

Thank you very much for the trouble you have seen and info you have been sharing here for this type of charger.
I have two 8kW tcchargers one is on my car and working well, witch I use if I charge at charging station from mennekes connector witch is here 3 phases 3 x 32A 400V AC (between phases). And then I have paralleled on the battery side 3,3kW chinese charger with it and they work fine together.

Other one I have 8kW 72V tccharger, witch had accidently in race hurry, connected between phases in europe that means 400V AC. It consists of 4 2kW modules. It has two sides two heatsinks with two AC ventilators. One heatsink has two 2kW units on it.
Strangely only one module was hurt and of course it had to be the master module.
There was 1 of three big 220uF electrolytic capacitor blown, relay contacts welded together, rectifier bridge shorted and 30A fuse blown. Those components I have changed and connected it to the grid, it started up but it doesn't work properly no more. One (slave) side seems like ok its LED blinks red_green like it should when battery is disconnected. Other unit had only green light blinking. And master control board has red led blinking.
I have read your suggestions on repairs, and problems those chargers have. All systems seem to be ok except Low voltage SMPS gives out too big voltages. Here are my measurements:
Testing with 2 lab supplys in serial 52V current the charger took: 70mA
Low voltage SMPS: control board output 13,9V
and relay output 15,3V measured microprocessor voltage from black socket it was 3,3V
viper control circuit IC: on pin 2 =13,3V and pin 4: 1,98V
does it help if I change the viper IC I think it works but why does it give so high voltages? Does it matter for the control board uP?
I gave 12V from control pins and the control boards small red led started blinking the same as with 50V power on main power wires.
Attachments
Ruudi controlboard type.jpg
Ruudi controlboard type.jpg (203.49 KiB) Viewed 250 times
Ruudi red led.jpg
Ruudi red led.jpg (246.6 KiB) Viewed 250 times
Ruudi 8kW tccharger.JPG
Ruudi 8kW tccharger.JPG (1.19 MiB) Viewed 250 times
Ruudi two modules separated.JPG
Ruudi two modules separated.JPG (1.25 MiB) Viewed 250 times
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:39

This is not the latest version of this post. There may be a later one archived, accessible at a later time.

Warning: if the mains input is connected to actual mains, the "GND" mentioned here is at lethal potential to the ground pin of the mains, and your body. In other words:
GND is HOT!
I believe that these jumpers are only intended for use with a current limited power supply of about 50 V.


I've finally sussed out the use of the three main jumpers on the Elcon/TC charger daughter board (the one with most of the chips on it, including the processor and small red LED).

J8: short to disable the PFC stage. This is a good thing when debugging with a 50 V current limited power supply, because the MOSFETs will switch at 50 V rather than 385 V.

J7: Short to force 240 V mains detection. Without this jumper, the mains sensing circuitry will decide that your 50 V power supply is too low, and will disable both the PFC stage, and the PWM stage. So the MOSFETs won't switch at all.

J3: Without a battery detected, the microcontroller won't enable any switching. By inserting a jumper with a 1.8 kΩ resistor (see below), you will get a moderate duty cycle. This is ideal for testing. [ Edit: I used to recommend a 3.3 kΩ resistor for a very low duty cycle, but on some chargers, there isn't enough voltage to get the UC3846 to start generating pulses. ]

So the sensible combination of jumpers is as follows, in order:
1) All jumpers out. 50 V across the main MOSFETs, but they are not switching. Good for finding shorted MOSFETs. Leave the power supply current limit at 0.5 A or less.
2a) Optional. Only J3 in. For the truly cautious, this will give the MOSFETs a short burst of switching, then immediately stop switching them (as it realizes that the mains is not present). You should be able to measure part of the voltage from the next step at the output, slowly decaying. It might be only a half or even a quarter, so a peak of 4-12% of maximum voltage, or 5-16% of nominal voltage.
2b) All jumpers in. 50 V across the MOSFETs, which are now switching. You should see some 15% of maximum rated voltage (about 20% of nominal voltage) at the charger output (negative output terminal and PCB pad, see below). Power supply limit can stay at 0.5 A or less.

At this point, you should be confident that the MOSFETs are switching properly, because the energy in the bus capacitors is about to increase about 8² = 64 times. Use a DSO if there is any doubt.

3) J7 in, J8 out, J3 out. Now there should be ~ 385 V on the DC bus (the MOSFET power supply), but the MOSFETs are not switching yet. The power supply current limit needs to be at least 2 A, preferably 2.5 A, to get started. It may take ~10 seconds to get close to maximum bus voltage, at which point the current should fall to around half an amp (it jumps around a lot on my power supply, which is two 25 V supplies in series).
4) J7 in, J8 out, J3 in. Now there should be ~385 V on the DC bus, and the MOSFETs should be switching. The power supply limit needs to be at least 2.5 A, preferably 3 A. Now you should read about 110% of the maximum rated voltage (about 150% of nominal voltage) at the charger output. This could exceed the voltage rating of the output capacitors; if so, don't leave it running like this for very long.
If it passes all this, it's time to reassemble the charger and test with a real battery and mains power.

Here is my collection of jumpers:

Jumpers3.jpg
Jumpers3.jpg (83.91 KiB) Viewed 248 times
The jumpers appear to be 2.5 mm spacing, but I used the more commonly available 0.1" header pins (2.54 mm spacing). The slight mismatch makes them stay put without falling out. Note: there is black junk over all of the jumpers, in fact over 95% of the PCB, so you need to clean the area around the jumpers. Also, the holes fill up, which is a royal pain. I use a paper clip to push through the holes. You may need to clean the back of the board where the jumpers come through as well. A wooden chopstick, flat at one end and sharpened at the other, is useful for this. I sharpen the pointy end with a pencil sharpener, and the flat end with a small file. (Thanks for the idea, KennyBobby.)

The two jumpers at the left are shorted; the heatshrink is to keep them together and to make them easier and safer to handle.

Here is the location of the jumpers, and some close-ups:
Jumper locations broad.jpg
Jumper locations broad.jpg (296.85 KiB) Viewed 248 times
Jumpers J7 J8.jpg
Jumpers J7 J8.jpg (67.43 KiB) Viewed 248 times
   
Jumper J3.jpg
Jumper J3.jpg (75.35 KiB) Viewed 248 times
   
GND via.jpg
GND via.jpg (70.76 KiB) Viewed 248 times
Power connector.jpg
Power connector.jpg (128.62 KiB) Viewed 248 times


The power connector on the left of the control board is useful for connecting to ground with a multimeter negative lead or DSO ground lead (though you get tons of glitches when the MOSFETs are firing). I had a plug already made up, but only plugged it into the top pin, so there was no danger of shorting the 15 V power supply. For temporary multimeter negative leads I often use the ground via circled in orange. For +15 V, the top of L1 (in the top left hand corner of the PCB) is handy.

At the output of the driver chips (U15 and U16), you should see ~ 12 V p-p on the low outputs (pin 1), and around 60 V p-p on the high outputs (pin 8). The latter is because you are adding the ~ 48 V from the MOSFETs switching (50 V from the power supply less some diode drops), plus the ~ 12 V from the boost power supply (pin 7, this should be a square wave with the low end around 12 V to around 60 V at the top end, about 12 V higher than the MOSFET outputs).

When all is fixed, you should see some DC output, but not at the actual positive output terminal. This is because the micro doesn't see a battery, and so won't connect the output relay. [ Edit: actually, there is a resistor across the relay, so you should see something at the positive output terminal. ] But there is a spare relay position (only populated for very low voltage chargers whose output exceeds 20 A), where a multimeter positive lead can be conveniently placed:

Relay pad output.jpg
Relay pad output.jpg (114.11 KiB) Viewed 248 times
The negative lead can be placed on the negative output terminal (not interrupted by the relay being open), or the negative output lead if it's still connected.

In my case, I was working on a 288 V nominal unit with a 13:7:8 transformer ratio (many of the transformers seem to have their ratios written on them, particularly the 2 kW units). The :7 and :8 parts add; only the higher two voltage units have this arrangement. Treat it as a 13:15 ratio transformer. Lower voltage chargers will have rations like 13:9 or 25:8. In my case, I expect roughly 15/13 x 50 V = 58 V; I was seeing a little over 60 V.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:45

I'm fairly confident now what the SOT23 devices marked A1t are: BAW56 high speed dual diodes, available from Newark and no doubt other suppliers. It's confusing because some of them have D designators (as you'd expect from a diode or dual diode), and some have "Q" designators (as you'd expect for a bipolar or MOSFET transistor). Now that I believe I've nutted out the desaturation protection circuit (I'll post that soon), it all falls into place.

One of the diodes I pulled out recently had marking code A1t (no serif on the bottom of the "1", and the "t" looks like a dagger) and what looks like "98" on its side. My replacement has marking code A1W in a similar but not identical "font", and "38" on its side beside it.

The third digit isn't part of the part code; it's a country of manufacture code. "t" just means Malaysia, "W" means China. So I'm pretty confident about the match.

[ Edit: the other parts in the attached list are variations on the same part: different packages, some with more than 2 diodes, and so on. Only the SOT23 variant has the bare "BAW56" type number. ]

[ Edit2: For a while I thought it might be this P-channel MOSFET, which also has a marking code of A1, but it's not clear if there is a country code after that. I suppose there is still some chance it might be that MOSFET. ]
Attachments
BAW56 marking codes.png
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 07:49

Attached is the desaturation schematic for the Elcon/TC chargers, as nearly as I can figure it. Thanks is due to Weber, for giving me the clue that this part of the schematic is probably about desaturation protection. When the lower MOSFETs are on, the 1K resistors (R59 and R63) pull C36 up to one diode drop above the highest MOSFET voltage. When the MOSFETs switch such that the output is high, D5 and/or D6 reverse bias, and C40/43 hold the voltage relatively steady. Q4 on the daughter board (Q4d on the schematic) seems to pull this voltage low during the time that the PWM chip's oscillator thinks it's dead time (upper and lower MOSFETs both off); this is around 200-250 ns. Actual dead time seems to be more like 450 ns, due to delays caused I think mainly by C29/C30 (on the main schematic, not shown in my attachment).

The basic idea seems to be, if the lower MOSFET starts to desaturate (due to over current, for example), then the cathode of D5/D6 starts rising, the anodes rise another diode drop above that, and C36's voltage starts rising. This causes the CS+ PWM chip (U14) input to rise. These chips are designed to current regulate, so as the current sense input rises, the PWM ratio decreases, and the MOSFETs work less hard (hopefully, reducing the desaturation, and saving the MOSFET from catastrophic failure). Obviously, this is not foolproof, as the charger I'm repairing testifies. But this seems to be the intent of this part of the circuit, and hopefully it does prevent blowing up MOSFETs in some circumstances.

I've seen this part of the schematic "hunting". It actually causes an audible screech as the current increases and decreases in a rapid and rather haphazard manner. When I disabled the gate for MOSFET Q3, I found that 2 of every three pulses generated were extremely short ones. I think this was the desaturation circuit in action. As part of drawing this schematic, I noticed that the R12 and R18 gate resistors were high resistance (8K and 13K), way above the nominal 1 ohm. I'm guessing that's actually why Q3 was getting hot. I spent a large part of today replacing U14; until I figured out the desaturation circuit, I figured it must be bad because I was getting the 2 of three pulses short on A OUT but normal square pulses on the B OUT pin. I misread the datasheet, thinking it was saying that the outputs are essentially complementary (it was actually saying that the UC1847 chip has inverted outputs compared to the UC1846 chip, sigh). Replacing the PWM chip (U14) had no effect.

Comments welcome on any corrections to my description.
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Elcon desat1.png
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:22

This photo was obtained after much effort: heating and carefully scraping off yellow gunk, while attempting to retain as much as possible of the solder mask, and removing white gunk (silicone) from C38. C2 and C46 are also difficult to remove, both because they are covered in yellow gunk, but also because they connect to non-thermally-relieved pads with thick copper cable reinforcing.

MOSFET caps.jpg
MOSFET caps.jpg (172.63 KiB) Viewed 244 times
I've updated the schematic to indicate that C46 has the value 220 pF, at least for the charger I was working on. Some chargers seem to have 2 kV rated ceramics, others 1 kV. I guess they just use what is available. C2 always seems to be 2.2 nF (0.0022 uF).

So you can de-solder the capacitors, here is where they are underneath the board:

MOSFET caps under.jpg
MOSFET caps under.jpg (273.01 KiB) Viewed 244 times
So C38 is my last hope for a failed component that could explain the blow-ups of this charger. The blow-up this time was even more spectacular than last time, with some copper snot ending up on the next MOSFET, giving it a sort of knobby knee :eek:


Image   Image

As far as I know, the other 2 MOSFETs are still OK, but I'll likely replace them since they've had a hell of a shock, so to speak. I'm part way through removing C2/C46/C38 in this photo.

The Samyoung capacitor has somewhat underwhelming specifications for the main DC bus decoupling capacitor (with C2 doing the very high frequency decoupling). It's rated at 105°C (good), 3000 hr (ordinary, but described as long life), 1.1 A or 1.0 A of ripple current at 120 Hz, to be multiplied by some 1.4x at > 10 kHz (so that's 1.5 to 1.4 A), and it doesn't even seem to have an ESR figure at all!

In another charger I have here, I see an EPCOS B43252 series (105°C, 2000 hr, and 1.42 A @ 120 Hz). Next, a Nippon Chemi-con KMM series (actually a decent capacitor manufacturer), 3000 hr, 105°C, 1.45 A ripple current.

In yet another, a Nichicon (again, good capacitor manufacturer) (L)GL series: 2000 hr, 0.78 A ripple, no ESR rating.

[ Edit: in a charger where at least 2 of the capacitors vented, they used Lelon LSM series (105°C, 1.14 A ripple current, 905 mΩ ESR. All these are 25 x 40 mm form factor.
I have been using a Panasonic EETED2G221JJ capacitor (105°C, 2.03 A @ 50 kHz ripple current, 603 mΩ ESR) replacement, but I see that these are discontinued now. ]

So I'm thinking that C2 must be doing all the hard work with the ripple, and perhaps the other three capacitors in parallel, even though they are in the PFC section, separated from the MOSFETs my two ~ 100 mm (4") links.

Or maybe I need to get or borrow an ESR meter. Or cobble one together.

[ Edit: the "1" in the top photo is the track that I missed a few days ago, buried under C38 and lots of gunk. Until I figured that this part of the resistor network was connected to something else, I didn't recognize the back to back diodes as D2/D3, or the array of 15 0805 resistors as R33/R4, already there on the original schematic. ]

[ Edit: added under-board photo. ]

[ Edit: added photo of C100/C6. ]
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Samyoung C38.jpg
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:27

Having failed to find anything wrong with the capacitors C38 (large electrolytic), and C2/C46 (small blue ceramic capacitors) in the charger I'm repairing, I've decided to take the advice of a colleague and attempt to separate the gate control signals from the drain/source output signals. Last time we were testing, he detected faint crackling sounds, almost like high voltage arcing over. I thought that could surely not be the case, since arcing would create a fearsome bang. But he suggested that perhaps something was leaking slightly, causing one of the MOSFETs to start conducting when it should not. This is not a problem until the CPU directs the PWM chip to start switching all the MOSFETs; when its companion on the same half-bridge switches on, there is "shoot through" (two transistors conducting from bus+ to bus-), and then the fearsome bang came on cue.

Throughout the charger, there is generally at least 5.08 mm (0.20") pin to pin between any components with high voltage. The MOSFETs are a glaring exception; these are TO-220 devices (so many of them are) with 2.54 mm (0.10") pin to pin spacing. There are thick tracks to the source and drains of the MOSFETs, to reduce inductance and resistive losses. This makes the solder connections bulge somewhat, reducing the gap between for example between drain and gate. It is possible for all sorts of material to bridge that gap - resin from soldering, bits of insulating material (black, white, and yellow gunk), and so on. Dust and moisture can creep across this bridge, allowing an arc to form. The drain jumps from bus- to bus+ in a short time (a microsecond or two I believe) when the upper MOSFET turns on, so even if there isn't much conductance, there can be capacitance coupling the drain to the gate of the bottom MOSFET. All this is encouraging shoot-through.

His suggestion was to cut an air gap between the pins if possible, or stagger the leads a little (so they form a triangle rather than a straight line), or both. It turns out that the former was more possible than I thought, since there is the large cutout in the PCB for the heatsink, but there isn't clearance for the repositioned drain lead.

He also mentioned that I needed to clean off as much of the burned epoxy (now from two sets of blown MOSFETs), as the burned epoxy would presumably contain a lot of carbon, which is of course conductive (in that form).

Dremel slots.jpg
Dremel slots.jpg (190.36 KiB) Viewed 243 times
The above was taken before I extended some of the slots a bit further. You can see an area at the left where I started to make room for a staggered drain lead, but decided that it would just make the clearance issues worse.

I was also not vigilant last test for scratches in the solder mask:

Scratched solder mask.jpg
Scratched solder mask.jpg (234.09 KiB) Viewed 243 times
The yellow circles show areas where the solder resist has been scratched, revealing bare copper. It happens that these are gate leads (marked with a red "G"), near a B+ area (also scratched!) and a drain/source/output track (marked D/S). These also connect to CON32S, the 32-pin connector between the main board and the control (daughter) board. So again, gate signals are routed very near drain/source signals, and I had been removing black gunk from components to read their values and so on. So I'll be using some silicone or the like to protect these areas from creepage before the next test. The scratched solder resist will of course also end up under silicone.

[ Edit: In the above photo, you can just make out the values for C2 and C46: 2.2 nF (marked as 222K) and 220 pF (marked as 221J). These happen to be 1 kV parts; some chargers have 2 kV parts. I think they just use whichever is available. ]

So now I need to replace the MOSFETs again, hopefully for the last time. These holes have no thermal relief, there are heavy copper wires right up close to the MOSFET leads, and the PCB is extra thick to take the weight of all the magnetics (1.8 mm (0.0709", 9/128") instead of the usual 1.6 mm (1/16"). All these factors make it very difficult to remove the solder from the holes, using either a hobbyist solder sucker or solder braid. I don't have access to a proper desoldering station; maybe one day.

I've had success in the past using pins. Pins are usually made of steel with a thin coating that doesn't stick to solder all that well. But the usual household pin is about 0.6 mm diameter. The MOSFET leads are about 0.7 mm across. I tried quilting pins (0.7 mm diameter), hat pins (also 0.7 mm diameter, but lovely and big), and various sizes of safety pins. The safety pin was tolerable, but the coating was adhering to the solder too much, so I had a lot of trouble getting the pin out one it poked through.

In the end, I used ordinary sized paper clips; these are about 0.8 or 0.85 mm diameter. They are cheap enough (and I'm pretty cheap :)) to simply cut and discard:

Paper clip.jpg
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Here you can see the clip has poked through the hole and rotates freely, but a lot of solder has adhered to the clip, making it very hard to remove. So now I merely cut the paper clip with side cutters, and the clip having almost no solder away from the end comes out easily.

In the left of the above photo you can also see R13, which is 1.5 mm x 38 mm of tinned copper wire. This was mentioned recently by KennyBobby; thanks, Ken! Normally this text is hidden under a piece of heat conductive insulating material, and in some cases also under a piece of foam that holds it gently away from the chassis of the charger. That's a 2 kW charger; the layout is slightly different for 1.5 kW models, but the resistor appears to be identical.

[ Edit: middle photo had some tracks mislabeled. ]
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:32

I must be the only schmuck attempting to repair these chargers at the moment. I got all the way to testing with a real battery recently, when I decided to pull the plug before it connected (last time when it turned on the output relay was when the MOSFETs blew again). I did this because I heard the soft cracking sound that my friend (who is kindly loaning the battery, part of his EV pack) thought he heard last time. Last time, I wasn't sure if it was just the input relay doing its normal thing, but this time we both agreed that the crackling sound was back.

He suggested we do a "binary search" for the cause of the sound. We disconnected the battery, since this would allow us to leave it turned in without actually connecting and possibly failing again. Using a piece of tubing as a crude stethoscope, we listened in one half, then the other. We were able to determine that it was on the PFC (mains) side, not the output side, before it stopped happening. My friend thought it might have been coming from the input relay.

I formed a theory about how the DC bus voltage might be too high, so the PFC chip might be shutting down due to over-voltage (there is a divider chain dedicated to this purpose, which seems to trigger at 425 VDC design center). This was aided by me misremembering the DC bus measurement I did at home; I thought it was 460 V. (The bus capacitors are all rated at 400 VDC, so that would be bad long term, not too bad short term.)

But I re-measured, and it's around 392 VDC with either 240 V mains, or with 48 VDC. That's 98% of the 400 V rating of the capacitors, but I believe that they are designed to run at 385 VDC (when running off 220-240 VAC mains), which is over 96% of their rated voltage anyway. The MOSFETs are rated at 550 VDC, so the extra 7 V isn't going to cause the MOSFETs to blow.

I decided to take a closer look at the input relay itself. As you can see, there is a small darkened spot near where the contacts are:

Input relay Chris.jpg
Input relay Chris.jpg (137.41 KiB) Viewed 242 times
The yellow gunk is from the manufacturer, to keep the tall parts from being affected too badly by vibration. There is also printed circuit lacquer from my having conformal coated the whole PCB. The darkish spot circled in red is hard to see at most angles; that photo happened to capture it pretty well. So is it significant?

This is inside the relay cover:

Input relay cover Chris.jpg
Input relay cover Chris.jpg (42.92 KiB) Viewed 242 times
It's starting to look a bit more serious, but maybe relays always do that.

Here is a closeup of one of the contacts:

Input relay contacts Chris.jpg
Input relay contacts Chris.jpg (83.05 KiB) Viewed 242 times
You can see that it's taken a bit of a blast at some point. It would have opened under load twice when the MOSFETs blew; there may well have been significant over-current due to the shorted DC bus each time. The input relay always sees AC (unless you run the charger from DC; my testing at 50 VDC was always at quite low current, 2 A maximum). The relay contacts are rated at 250 VAC and 16 A, or 30 VDC and 16 A.

Any opinions on whether the contacts are seriously damaged? They seem to measure low resistance and with a reliable connection, as judged by a cheap multimeter on the beeping continuity setting. (I have a Fluke that removes the "scratchy" sound you get from cheap multimeters when lightly rubbing the probes together; in this instance, this feature is unwanted).

In particular, should I carefully and lightly sand the contacts with very fine sandpaper? This could remove some of the blackness, but may also remove some of the miracle coating that the contacts may have.

The input relay is an Omron G2R-1-E with 12VDC coil.

The way to remove the relay cover (after removing as much as possible of the yellow gunk) seems to be to grasp it firmly with a large pair of pliers. This has the effect of making it bulge slightly, which releases the two clips at the bottom (which are difficult to reach due to the tall components nearby). I suggest replacing the yellow gunk with silicone when all is done.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:35

weber;751530 wrote: I remind you that, although the sound went away suddenly while we were still trying to narrow it down, that relay was in the quadrant that we'd narrowed it to, and when I listened right at the relay (and only there) I could hear a very quiet sound that was of the same character as the louder crackly sound we had both heard.
Well, it turns out that the sound was not from the relay at all (contacts or coil), but from the 2.2 uF capacitor right next to it. It is best heard through a tube "stethoscope" aimed right at the middle of the largest face of the capacitor. This was vastly easier with the capacitor soldered under the PCB:

Testing cap under PCB.jpg
Testing cap under PCB.jpg (204.99 KiB) Viewed 241 times
When we removed the old capacitor, we wondered about the discoloration in the white gunk (as opposed to the yellow gunk and the black gunk! :roll: ) under the capacitor:

Under PFC cap.jpg
Under PFC cap.jpg (127.74 KiB) Viewed 241 times
But we decided that this wasn't a contributing factor.

There is another of these 2.2 uF MKP polypropylene capacitors across the mains input. We swapped the two capacitors, and found that the other capacitor made the same soft sound: a faint crackling. We left the charger running for an hour or two, and did not notice the louder version of the crackling. So the louder crackling seems to be an intermittent feature of the original PFC capacitor (the one between the relay and the bridge rectifier).

I ordered new Epcos replacements (now owned by TDK), and soldered them in place. I now could not hear any sound, but was this because it was so hard to get to the large face where the soft sound was coming from? I thought to solder one of the new ones underneath the PCB, but then it might be different because I had the new capacitor in place already. Removing the capacitors and especially cleaning the holes of solder is a considerable pain. So I soldered the *old* capacitor under the PCB first. I could hear a faint crackling, but it seemed much fainter than at Weber's place, where there wasn't a new capacitor soldered across it. Now I replaced it with a new capacitor under the PCB (still with the other new one on the top of the PCB), and found that the new capacitor also made the same faint crackling sound.

So these capacitor seem to be slightly acoustically active. I tried searching for this, and found that some ceramic capacitors act a bit like piezo electric sounders, and that there are ways of circumventing this problem. Of course, I found lots of pages about amplifiers causing crackling *through the speakers*, but that doesn't seem to be relevant.

Anyone else come across acoustically noisy capacitors before? (Apart from ones that have failed and oozed goo or the like, of course.)

Edit: Just to be clear, my tentative conclusion is that the faint crackling seems to be normal, though some brands or models may be noisier than others. The intermittent, louder crackling that could clearly be heard without the stethoscope, seems to be abnormal, and I hate to think what is happening when it comes on.

Edit 2: The more I think about it, the more I think that there wasn't anything wrong with the original capacitors, and that the intermittent loud crackling is due to intermittent behavior of the PFC stage. I wonder if it coincides with control tones on the mains, or if the PFC stage intermittently just goes mad. If the latter, it might explain the MOSFETs blowing up, through a higher than normal DC bus voltage.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:40

It's possibly obvious, but since it just happened to me, I thought I'd point out a problem that can happen when reassembling the heat-sink clips:

Dont clip like this.jpg
Dont clip like this.jpg (93.76 KiB) Viewed 238 times
If you managed to leave it in this condition, the heat-sink clip would short out all the MOSFET drain connections. This is considered harmful :eek:

The clip needs to end up on the black epoxy of the MOSFETs.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:42

I'm at Weber's house testing the repaired charger (so far so good).

But before charging, we decided to check for crackling sounds (using his far superior ears). Yes, the new after-bridge capacitor was making a very similar sound to what the original capacitor was, when it wasn't being very noisy.

But before that, at first switch-on, he yelled to turn off the power, he saw a puff of smoke! Arrgh - what now? All I had done since last test was to change the capacitors and also the relay. Oh wait - to get to the relay I removed the pre-charge resistors, and part of the pre-charge resistor always seems to come away with the yellow gunk. So I replaced them with new ones. New wire-wound ones, because I could never understand why the manufacturer stuck with carbon composition types* that burned up so badly whenever the power supply failed (often due to other failures). We suspected the new resistors, so we powered up again and noticed a puff of smoke from the resistors, but it didn't continue. Obviously, when the relay turns on, the pre-charge resistors are shorted, so they dissipate now power. Sure enough, every time we started the charger, they would emit a little puff of smoke, but otherwise appear to be OK.

I then realized that each resistor is seeing the full 240 V at start-up, so that's initially a power of E^2/R = 240x240/150 = 384 W. Wow, that's a big overload for a 2 W resistor, just for a short period of time. Maybe the originals were 3 W or 4 W, but even so, it's obvious that high peak power types are required there. Ordinary wire-wound resistors are never going to achieve that.

Maybe the resistors can handle it; they seem to have the same resistance after a half dozen starts. But it seems like a bad idea.

I'm not sure what to replace them with. Perhaps two 5 W high pulse power resistors (these are wire wound, but with epoxy and a heat-sink). Or carbon composition resistors with a slow-blow fuse in series (say a 1 A 20x5 type). But it would take a lot of trial and error to get the fuse rating right, not causing nuisance blowing and yet still protecting against massive overload. Maybe a thermal fuse would be better than an electrical (current based) fuse.

* Edit: see post after next; it seems they aren't carbon composition types as I had guessed. Also, it seems that some wire-wound resistors are good at high pulse power too.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:43

Original post by Pdove:

Yes, kennybobby and I did that calculation on the first couple we repaired. They all had these resistors burnt to a crisp. We puzzled over a way to power up the viper before the relay closes instead of going through these resistors but we never tried anything. It's a very common failure since any problem with the viper power and that relay opens and they get full power. Maybe they are meant to fuse but seems like the wrong component for that.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:45

Coulomb;755202 wrote: ... I could never understand why the manufacturer stuck with carbon composition types that burned up so badly whenever ...
It seems that my guess was wrong. Here is one of the original 150R pre-charge resistors split apart with a chisel:

Inside pre-charge Rs.jpg
Inside pre-charge Rs.jpg (129.45 KiB) Viewed 236 times
I should have realized that they weren't carbon composition by the end caps**. The white material in the middle is totally non conducting, likely ceramic. You can see the spiral grooves that they use to trim the resistance of metal or carbon film resistors. By the dark color, and the smell when they burn up, I'd guess they are carbon film types, but I would not know.

So I think that the original pre-charge resistors aren't particularly specially chosen for their pulse power rating; perhaps they merely use coatings and paint that can tolerate the high temperature extremes from a pulse of power.

[ Edit: after a little reading, I think they may be metal oxide film resistors, which are good but not the best for high pulse power. ]

[ ** Edit 2: It seems that some composition resistor types also have end caps, especially ceramic composition types. So that's not the way to rule in or out whether a resistor is a composition type or not. ]
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:47

I finally settled on these replacements:

Aus: https://www.digikey.com.au/product-deta ... -ND/823910
USA: http://www.digikey.com/product-detail/e ... -ND/823910

Image

They're only 1 W continuous power, but that's because they're ceramic composition types (more or less the modern equivalent of carbon composition resistors), which use the whole body as the resistance. So they can't get rid of the heat from inside the core of the resistor as well, but that makes them ideal for absorbing energy pulses. At 250 V, the resistors need to absorb 50 J between them, and these can do 50 J per resistor. They are also the same colour and about the same size as the originals; the only difference is the 10% tolerance compared to the originals at 5%. But exact resistance value is not important, as far as I can tell.

They're about 100x as expensive as the wire-wound types, but still only a few dollars for a single charger repair.

But I don't know what they are like for overload. They could well hang on for dear life. So I might investigate some thermal fuses as well. Ah, they could replace the longer leads of the pre-charge resistors, like the attachment.

The middle pads, which normally take the longer leads from the resistors, connect together. All three components could be siliconed into a blob for mechanical strength, insulation, and thermal connectivity.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:51

It seems I never posted about the measurements possible without removing the PCB. I'll place them here.

It's hard to jam a multimeter probe at the bridge leads, at least while the heat-sink clamp is in place. Fortunately, the line end is accessible through the junction of the two long ends of the pre-charge resistors. So to measure the value of the pre-charge resistors, you can measure between there and the line input. This includes the resistance of two line chokes, but their resistance is negligible. It should measure 75 ohms, give or take about 10%.

Positive output from the bridge rectifier is easy to get to; it's the pin that's a larger distance from the others, towards the edge of the board, and accessible via a large pad.

Negative output from the bridge is essentially "GND"; there is a marked pad (it might be under some yellow gunk), and it also makes it to the output side of the board via the top side red jumper.
[ Edit: on the 2 kW chargers with three capacitors on the mains side, it is in about the same position relative to the large PFC inductor. In other words, the extra capacitor is nearer the yellow power supply transformer and power supply chip with the small copper heatsink. ]

The other AC input lead to the bridge rectifier connects essentially to the Neutral input.

So now the four pins of the bridge rectifier are accessible: L and N are the AC inputs, negative output is "GND", and the positive output can be accessed by the large pad.

[ Edit: the positive output of the PFC stage, the "DC bus", is easiest to get to near the big capacitor on its own, where there are several vias, as shown. ]

2018/April: Finally, more of an observation than a measurement. If the processor is flashing its small red LED or the red/green LED, then you know that the 12 V power supply is working. If the input relay pulls in, then you know that the 15 V power supply is working (presuming non-welded contacts). Both of these tests can be done with a ~52 VDC power supply applied to the mains input.
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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:53

Now some repairs possible without removing the PCB. This one is replacing the 150 ohm pre-charge resistors, which often get burned up through various mishaps. In my case, I needed to replace the wire-wound resistors (from a previous repair, actually just getting clearance to replace the input relay) with ceramic composition types, because the wire-wound types were emitting a little puff of smoke with each switch-on of the charger. During the first 100 ms or so, these resistors are required to take up to 50 Joules between them, with a peak pulse power of nearly 200 W each.

I also wanted to try adding a slow-blow fuse, as posted recently. Back then I suggested a thermal fuse, but a slow-blow fuse of suitable rating should be about as good. I chose a 750 mA part; it seemed to be a good compromise between not nuisance blowing with the large surge of current, and blowing in 10 seconds or so if the resistors end up across the mains.

You can see the before and after photos in the attachments. I did the whole repair from above the PCB, but I found that after it was done, the fuse no longer connected to the bridge rectifier. So I was forced to take the PCB off after all :mad: It turns out I damaged the pad under the fuse. It looks like it would have been better to use the hole that is slightly further away from the edge (i.e. the one for R1, not the one for R23). It has a reasonable sized track attached to it, so it may survive the rigors of clearing solder from the pads better than the other pad. (Both middle pads connect to the same place; there is a small sliver of track between the two middle pads.)

You can also see one of the hassles of repairing from above the board: the shiny plastic gets in the way, and it's nearly impossible to avoid burning it with the soldering iron. (Hence the hole burned in it.)

Edit: the ceramic composition resistors seem to work well. With each switch on from 240 VAC, there is about a 5°C temperature rise, which dissipates over a minute or two. The 750 mA slow blow fuse also seems suitable, but really only time will tell if it will nuisance blow too soon.
Attachments
Ceramic R repl before.jpg
Ceramic R repl before.jpg (156.63 KiB) Viewed 234 times
Ceramic R repl after.jpg
Ceramic R repl after.jpg (174.84 KiB) Viewed 234 times
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:57

I struggled to replace a transformer today. I remembered the solution was something to do with very small pieces of Blu-Tack, but I was trying to place the nyloc nut with pliers. Eventually it came to me that you use a Philips screwdriver to place the nut, and attach the nyloc nut to the end of it with the Blu-Tack, as attached. You position the nut over the bolt, using another screwdriver to bend the bolt to a suitable position if necessary. The idea is to use the temporary connection of the Philips screwdriver to the nut to get half to one turn of thread on the bolt before the Blu-Tack gives way. Remove the screwdriver(s) and use a long nosed socket to complete the job (many, many turns). Repeat as necessary, but I find that this works pretty well first time almost every time.

[ Edit: Ok, the really hard one under the transformer cables may take a few goes :mad: ]

Using a Philips screwdriver to get the first half turn on the bolt or stud works well for all the nuts, not just the transformer bolts. Usually, the Blu-Tack won't be needed for the other cases; you can usually position the nut by finger or pliers, just balancing on the bolt or stud, but the half turn from the Philips screwdriver gives it a lot more stability for when you apply the long nosed socket.
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Blue tack on nyloc.jpg
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Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 08:59

I'm repairing a charger that has a direct short at the output of the bridge rectifier. It looks like it has to be one or both of Q7 and Q8, the PFC MOSFETs. I've never had these fail yet, and have never seen a part number for them, so I pulled one of them from a dead charger:

Q7Q8 MOSFET.jpg
Q7Q8 MOSFET.jpg (112.71 KiB) Viewed 231 times
It's an IXYS 600 V, 24 A (@ 25°C) 165 mΩ max device, datasheet here:

http://ixapps.ixys.com/Datasheet/IXKH24 ... 4N60C5.pdf

Edit: I expect a wide variety of parts could be found in these positions; this is just one of them.
Another had a marking code of 6R165P, which is an Infineon IPW60R165CP, 650 V, 21 A (@ 25°C), 165 mΩ max device, datasheet here:

http://www.infineon.com/dgdl/Infineon-I ... 2d915e489f

On the charger with the short after the bridge, the 150Ω resistors had crumbled.
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

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Re: TC/Elcon 2013 Charger Troubleshooting and Repair

Post by coulomb » Sun, 22 Jul 2018, 09:06

I find this image of the cleaned-up control board very useful. I thought one of us had posted it ages ago, but I can't find it.

2.17 MB Jpeg; 3264 x 2448 pixels.
Use your browser controls to zoom in if necessary. This link may help.
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ControlBoardBack.jpg
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Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

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