This post is for those who agree with me that the fans in any electronic equipment, if they act vertically, should blow air up from below, not suck out from below. Performing this modification will likely void your warranty, despite the fact that in my opinion, it will improve the cooling of the unit.
[ Edit: The other consideration is that dust tends to collect where the fans draw air into the unit. This is more readily accessible at the bottom of the unit, where the cable access cover can be removed with just two screws. ]
The top cover comes off easily, but you'll have to sacrifice part of the sticker with the year of manufacture. This is what you need to aim for, in order to be able to access the bottom two screws of the left hand fan; they're right behind the serial PCB:
NOTE: It's been shown that the following is the hard way to access the fans. I leave the following for historical interest and for the reader's enjoyment at my expense. Take out the serial board for much easier access.
If you don't get the plate holding the two fans this high up, then you'll never be able to remove and replace the bottom two screws on the left fan. Well, unless you have an amazing Z screwdriver that has a very short straight part. The two screws holding the fan plate to the box sides are easy to remove, but unlike earlier models, the PV input terminal block is now holding the plate firmly in place. The terminal block is screwed to a seat, as shown below:
The second photo shows the pegs that together with the screw and the tight fit hold the PV terminals in place. The third photo shows the three screws that you need to remove: one in the middle that screws into the seat, and the two holding the straps that connect the PV inputs to the SCC PCB. The other end of the straps is soldered to the SCC PCB; it would be a lot of effort to undo those, and these is no need. The terminal block comes out with a bit of wiggling and choice words.
At this point, the fan plate still doesn't come up, because of the two toroids marked 1 and 2 on the photo below, trapped under the printed circuit board marked 3:
By pushing the fan plate towards you, you can carefully work the two toroids out from under the printed circuit board. Finally, the fan plate can come up. Using a full sized #2 [ edit: was #3 ] Philips head screwdriver, the fan screws can be removed.
Oh, I've neglected to mention another test of dexterity and patience. There is a small cable tie at the bottom of the left hand fan, which restricts movement of the right fan. Using long nosed pliers, I was able to pull the cable for the right hand fan through the cable tie, but not far enough to be able to rotate that fan. I found the best way to cut the cable tie was to use a small flat bladed screw driver to rotate it slightly so that the bulge on the cable tie was facing away from me; I was then able to cut it with medium sized side cutters from above.
It is then a matter of taking the fans up, rotating them about the vertical axis (so they now blow inwards rather than outwards), and putting them back. You will be cutting new threads into what was the back of the fans (now the front), so that's another reason you need good access to all eight fan screws, and the need for the large #3 Philips screw driver.
Manipulate the toroids back under the printed circuit board, carefully as before. Replace the PV terminal block, screw the fan plate back, and replace the lid.
Edit 1: in retrospect, it might have been easier to remove the serial port board. You could cut the new thread in the fan plastic while the fans are out of the unit. I may try it that way if I decide to replace the fans with quieter ones.
Edit 2: Weber just reversed his fans without having to remove the metal plate that they are mounted on at all. Removing the serial port board is definitely the way to go. He may have rotated one of the fans 90 degrees to make the cables fit. He didn't even have to cut the troublesome cable tie.
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