Some months have gone by since my last post. This post should be (hopefully) the final resume of my repair, as the car is charging again! The news isn’t that new as, after the repair had been done, I have observed the car for quite a while to see if everything works reliably. Having had two setbacks in situations where I thought that I had fixed the issue made me become careful with announcing victory too early...
First setback was when I thought that I had only the "classical" snubber caps issue and after replacing them the car still wouldn’t want to charge. The second one was after a long troubleshooting on the control board and the discovery of many damaged ICs I finally completely replaced the control board by another one. It was not 100% identical, some components were not in the same order, even if it was the same chips. So, at this point I can’t say if the failure of the repair was due to overseen damage on the power board (seems to be the more likely explanation) or if it was due to incompatibility of the replacement control board (seems to be the less likely explanation).
So, my repair finally ended as an easy “plug & play” repair. Due to a lack of knowledge, experience, good soldering and testing equipment and a complicated damage scenario with damage on many ICs of the control board and probably also one or more undiscovered damage(s) on the power board, this turned out to be the most implementable solution for me: getting an identical OBC box form a scrap yard as a donor and exchanging the two boards. That worked...
After the repair the car was announcing a much higher range expectation than before. I thought that this could be somehow due to the fact that the 12V battery was weak before and that it was providing a bad reference voltage, but actually this explanation didn’t satisfy me. I got the correct explanation after some days, when the little turtle icon went on and I had to call a neighbour to tow me the last 3 km home: obviously the calibration of range expectation and state of charge (SOC) aren’t correct any more. When the turtle icon went on, the car was announcing 15 km of remaining range and 2 remaining bars on the SOC. I assume that this wrong calibration is due to disconnection of the main and the 12V battery during longer periods while the car was waiting to be repaired and that it will correct itself with time and charging/discharging cycles.
That’s it. I want to thank all the people that have contributed to gather the knowledge in this forum and especially those who actively helped me by answering my questions during my repair journey.