I’m with Inwo. I don’t see damage in the original pic that points to this area. It is tough to tell from the pics what the tech might have done here because the lighting and pic orientation changed 180 and not the same in both pics. (I flipped the first pic for consistency).
It looks like the conformal coating is still in place from around the diodes but may have been removed and replaced. Still visible all around C17.
Solder on D2 looks a little disturbed on D2 but it may be the coating.
If any of the diodes were replaced, the tech wiped the paint markings off the new components too.
The tech said probably a short that caused damaged.
Tech might have mentioned that the resistor might have popped.
There may be something that was lost in translation here. A resistor popping would be an open condition and not something that would blow a fuse.
I am curious as to why J3 Pin A is flagged with tape and the meaning of the little flag of tape down on the board next to C63. Looking in that area, there seems to be something going on between Pins J and K of J2.
Interesting that J2PJ and J3PA are the key switch wires we are interested in. Did your Tech pick those pins out himself or did you help him with that?
Edit: Looking at some of my other pics of the board, the above may be a light artifact of some conformal coating that was poured over in that area.
First things first. Want to thank you and other parties very much for the input and patience. I did learn a great deal about the workings of the car through the step by step diagnostics. I hope this helps others. My advise to others is to understand the division between the drive voltage (72v in my case) and all the other accessories that run on 12v.
Did you measure any voltage between your 72V+ and 12V+ or 12V-?
Did you measure any voltage between your 72V- and 12V+ or 12V-?
Because just one worn battery cable to the frame should not have blown anything because the 72V side is supposed to be ISOLATED from the vehicle chassis and electric system.
when I put everything back, I noticed the radio didn’t work but check for power all good took radio out and fuse blown. I don’t know how or when it happened.
I can’t figure how how that answers the question about the voltages measure between the 2 power sources. There should be no voltages measured because there should be no connection between them. After all, didn’t this all start when one of the 72V battery cables shorted out to the chassis?
Correct me if I’m wrong but shouldn’t that have NOT causes any problems in and of itself because of the isolation between the 72V and 12V systems?
All this happened when charge wasn’t working. Took charger out to get refurbished. When was placing the charger back something but have shorted out.
How, where and when still a mystery.
In theory, the two different systems are/should be isolated. I see it all the time that they are not. Using mixed reference points will get you a number.
I’ll call it stray/phantom voltage for now because they can be seen and measured, but I have not actually tried to run something from it. It might be backfeed from a diode or perhaps a hastily designed circuit and someone needed a ground.
There are three components that stray voltages might be sneaking through.
Controller
PSDM
Charger
Next time I get down that far I will see which one is leaking the most.
I suspect the controller might be responsible for most of this.
The base is a big aluminum heat sink screwed down to the shelf of the car for heat dissipation. Inside the controller are 30 or so FETs screwed down to that same plate.
Just gotta figure the OP blew things because something was wrong to begin with and they should isolate that problem too instead of just repairing the PSDM.
I think what you are missing what dougl was trying to point out.
We are very confused/concerned how the battery cable managed to produce such a bit arc when it rubbed on the frame.
Check to make sure something is not weirdly jumped where it should not be.
Put one probe on a 12v source and the other on B-.
Do you see any voltage?
Then do the same across B+ and ChassisGnd, and B- to ChassisGnd.
Do this test while sitting, and also when driving.
Does the voltage change?
Could have been when I was installing the charger/converter. When I was placing the ground from charger/converter to the controller and tightening the bolt the ratchet hit the frame and sparks flew. And yes the the switch was off on the PSDM
Yikes!!! You need to look close at all your cables again. It appears B+ is still attached/touching the Chassis!
Did you do anything to that cable back under the back seat?
–
Could have been when I was installing the charger/converter. When I was placing the ground from charger/converter to the controller and tightening the bolt the ratchet hit the frame and sparks flew.
This begins to make sense now.
And yes the the switch was off on the PSDM
The state of the MainBattDisconnectSw makes no difference. It breaks the B+ connection as it goes into the PSDM. Between the switch and the battery the cable is still very alive. In post XX you discovered the very live cable was so run over the corner of the frame so tight that it rubbed through the insulation. It was connected to the frame at that point.
When you were working up at the controller and had your wrench on the B- connection, You brushed the wrench against the frame and completed the circuit. → POW !!! ←
Yes cut a jacket from another cable, electrical and shrink wrapped. Cut in half a piece on 1-1/2” clear tubing and zipped tied to frame as additional protection
Yikes!!! You need to look close at all your cables again. It appears B+ is still attached/touching the Chassis!
0V! As I stated before, the 12V and the 72V power systems should be isolated from each other. You are one bad bump, loose wire or other away from a possible electrical fire or blown circuits.
