Tried bridging the 2 large terminals on the contactor to allow current flow but this didn't make a difference.
Applied 48V to the contactor and it clicked over fine and reads 0 ohms when energized, so it appears OK. So it seems the Sevcon isn't outputting a contactor charge to energize it. It's now just giving 3 flashes which indicates the controller is likely faulty

So it appears that I have a faulty Sevcon Millipak controller. Does anyone know where I can get one of these affordably? Most seem to be around $700-1000US

It's a model 633T46301.
Are some of the other visually similar models interchangeable? eg: https://www.cartpartsrus.com/SevCon/sevcon.htm
I think these work by switching things to ground, vs switching to positive, so not sure if I can change to another brand of controller.
If I was to buy a new Sevcon, would it need to be programmed also? Or just plug and pray?
Does anyone maybe have a good one they are selling?
I've pulled it apart and it's full of that black potting epoxy, so I'm going to have a hard time getting to the innards to try and repair it otherwise. Has anyone repaired one successfully? Any tips on getting the epoxy out safely?
Thanks for any help
