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I'm trying to repair a "red" CMU, i.e. one of the pre-2012 types with the red conformal coating. This one is weird. There is no 5 volts on the battery side of the isolation chips. It's an 8-cell board, and I only have one 4-cell board for comparison. I traced the problem to a 2SD1584 Dpak NPN...

Does the change from pre-2012 to post-2012 also mean a change in CMU board color (red to green pre to post)? Or is it all in the BMU firmware? Maybe the CMU firmware needs changing as well? It seems to me that the CMUs merely report what they see to the BMS, so the color of the boards should...

Indeed. But the key question is, is it the resistor itself that fails, or does it burn when the capacitor(s) fail? My guess is the latter. My assessment is that it's for thermal conduction. It's not stiff or hard, it's flexible and flaky like rubber. Not particularly stretchy like silicone. I...

I think so. I'd also consider adding a suitably rated fuse. These need to be rated at 400 VDC or higher. I'm suspicious about the long term reliability of SMD high voltage capacitors. So I'd consider through-hole replacements, as I used. I don't believe that 4.7 μF 400 V come in that smallish...

This post showed requests for DTCs going to and coming from the BMS, so not all DTC information comes from the EV-ECU. I agree that this looks like the ECU at $765/6 does not support these PIDs. If this is truly the OBC ECU, then it looks like the OBC posts things like battery voltage and...

As soon as the top board is unscrewed from these charrgers (2012 onwards), you have to deal with a flexible ribbon that connects the top and bottom boards. Conductors on this ribbon are spaced 0.5 mm (less than 20 thousandths of an inch) apart, so the connector is a delicate, precision part. The...

Those are not the smaller high voltage DC capacitors that frequently cause trouble, those are on the lower board. It would be worth inspecting those while you have the charrger open.

I wonder if the AC capacitors that ooze gunk can be spotted months before there is a problem. I also think that it's worth pre-emptively replacing the small high voltage capacitors, particularly if you have the SMD versions. You would of course replace them with higher voltage parts that...

Actually, this particular photo shows the Viper chip; the inductor must be on the other side. I'll go chase up the other photos soon. I noticed that the charrger got hot mainly in the top right hand corner, where that PWM module is located. Maybe they found that the control board too close to...

When re-assembling the charrger, I noticed a familiar-looking inductor (L402 below), and low and behold, there is a third Viper chip on the third module. I took these photos without taking out the module, using a mirror and bare phone out of its case (to squeeze it in to the tight spots): The...

Thanks a heap! I wish I'd used two 150Ω resistors now. Sigh.

It sure does! Thank you so much! I never thought about the other modules and how they get their power for isolated measurements. I'm sure it is, with pins 5-8 and 1-2 commoned. And L301 looks identical to L601. Yes, D314 looks like it's the "missing" diode, and it appears to be bigger than the...

It's possible. But I think that the diode has to be pretty fast, and moderately high powered, so I think that the regulation is via extra resistors on the FB pin that I haven't shown or traced. Yeah, that makes some sense. Also, it's probably a good idea to have some damping for the LC circuit...

Yes. It's a worry, but it seems to me that these Vipers are designed to work with high voltages, so they should be OK. I'll find out in a few days. No, I don't have inductance measuring equipment, and I didn't measure the resistance, sorry.

It tested fine; 16.0 V at the input to the voltage regulator, and 5.0 V out. This was with 52 V at the input of the power supply (representing the battery voltage). Now to put it all back together. It drew some 6 mA, for just over 300 mW. At more realistic battery voltages, it would presumably...

I thought that the DC-DC was on the CAN bus; the PHEV reports data on CAN id 0x377. But maybe you can't adjust the voltage that it aims for. Certainly other cars will charge the auxiliary battery at either float-like voltages (e.g. 13.0-13.8 V) or at bulk voltage (14.0-14.4 V), depending on...

Interim pictures of the output module repair. It's not tested as yet; I need to organise some power supplies. This was my first attempt at laying out the parts: I then realised that there was enough room to mount the capacitors directly on the PCB, and that this would probably result in...

Agreed! This circuit would presumably be active any time that the battery contactors are on, not just while charging. So you really don't want tiny PCB parts, especially ELBs ( :D ) powered with full battery voltage every time that you're driving, without decent protection. I'm a little...

I've decided that using a resistor as a high voltage DC fuse is not a great idea. So I'll use an SMD fuse. Alas, these are 11 mm long, so they won't fit on the PCB. I'll mount them and two ceramic capacitors Christmas tree style to the right of the board. [ Edit: Mouser and Digi-Key are out of...

It's a worry. I suspect that chip ceramic capacitors aren't very good long term with high voltage. Hence the snubber caps on the daughter boards failing spectacularly. So I think I'll replace C601 and C602 with leaded capacitors, if I can fit them safely. Hard to be sure, and I haven't checked...