Apparently so. Since you did not get 3V3 out, and CAN chip is bad, desolder the CAN chip and see if the FOCBox wakes up. If it doesn’t, measure the C25 and if it still doesn’t have the 3,3V, i would suspect the regulator(GH12E).
How powerful board are you going to make? Even one anti-spark circuit with one FET is enough for normal commuting.
I was joking with a friend via WhatsApp and ask him if he got some of those CAN chip around.
He sad no, I only got the newer version and then he gave me 10 of those:
Designed for operation in especially harsh environments, these devices feature cross wire protection, loss of
ground and overvoltage protection, overtemperature protection, as well as wide common mode range of
operation.
Oh well maybe just shitty chip… I usually use the ones with isolation…
I am not trying to prove anything I am just curious… That’s all, I have been working, with multiple CAN systems, and never run into the problem with ground loops…
I am just trying to understand how that happened so that I could prevent this kind of cases in the future.
First off that TVS diode with the white gunk on it is not blown, my brand new FOCBOX’s have it as well. Also why where you using two switches instead of just one connected to both FOCBOX’s? And I wouldn’t try using that different CAN chip unless it states it’s a drop in replacement and all the pins are the same.
You could wire the on/off switch in parallel to both antispark-switches like @esk8 did it. I don’t know if it’s necessary because the 40A fuse can take more than 40A for a short period of time, for example 60A for 10 seconds and even more for bursts. Also I don’t know what happens if you use 2 switches and only one fuse blows (or one switch dies), maybe you could harm the second FOCBOX as well. I had a single switch running on my MTB and the 40A fuse never got blown.
I would use 1 antispark-switch only and if you want a bigger fuse then you can desolder the fuse holder of the antispark and solder a bigger fuse like the one in the picture. 150A is too much but they are available in 80A. too.
JohnnyMeduse Fixed mine. Just send him pics of the inside of your foc box and he will let you know if he can fix them. It’s a bummer I fried mine as well.