holmoe

It's a little late to complain since this post is from 2023 ..but.. Almost all you wrote is ok, but you really have "overengeneered" the measurement. The ESR Tester from ludens.cl which was the hint from me, isn't a measuring device, it's build for fast tests. You don't even need a calibration on the meter which gives you numbers..you can use the instrument of an old VU meter or some such to get a fast good/bad test. Some experience is needed for identifying bad caps, but after a short time you know how a good cap is looking like on the meter. That thing that I'm regularly use has an resistance value of approx max 20 Ohms it can display and sometimes I misuse it to check source resistors in PSUs..they are ok .. or they are bad. An yes/no decision. Same as for electrolytics.. I don't want to "measure" values, I want to know if they are ok oder bad. The meter needle has to be in the zero range, all other positions identify a bad cap (except for 0,47 or 1µ Values). The ludens.cl Tester does a good job for this. I have a large stack of TL084 Opamps and made a small pcb for those testers ..using an precision rectifier..that was nonsense. It works better with the simple circuit with the two diodes for his purpose. I have the gear to do precise measurements at different frequencies and different polarization Voltages, but this HP 4285A Meter is more a furniture then a test device and it takes much longer to get yes/no results. just my 2 Cents, holm

@wael_fate: Check the Gate drivers and their power supplies from the bad Mosfets.Test the drivers and look at their output waveforms before you put any load on them. How this can be done is described in detail in the large Thread at https://forums.aeva.asn.au/viewtopic.php?p=97123 Regards, Holm

Yes, that's my own experience..but not only from repairing some inverters, I'm repairing industry-related electronics like VFD for motor control to make a living, that since 2007. Before that I was Unix system programmer and administrator. I only had exactly one (1) bad HV Cap from Siemens-Matsuhita in a large spindle drive of a CNC milling System. So you can have your own opinion, but I have mine. Regards, Holm

I think it isn't a very bright idea to change the 500V caps against 400V. The command QPIGS from my PIP4048 displays a BUS Voltage of 422Volts currently... Besides of that, those HV caps are almost never..ever bad. Regards, Holm

They dry out simply since it is very hot (to hot) in this area..I've suggested to add a FAN connected to CN12 (?) on top of the mainboard for efficient cooling of the upper left part of the machine. Kind regards, holm