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Francesc V. · 02-24-2026, 07:50 AM

Thank you all for your valuable feedback.

Some pictures from the inverter.

Not sure if I made some progress, but I realized that If I heat up just the heatsink (the "G40T60AN3H" 4 IGBTs) the inverter works for about 20 minutes.
The error that inverter gives is '03' that according to manual is (over temperature / output shorted).

Could it be that one of them be leaky? I guess that I need the 4 of them to make the sinusoidal output.

Next,I will remove the heat sink so I will be able to apply heat in a more...

Francesc V. · 12-18-2025, 07:53 AM

The picture shows already changed caps. The original ones (below) had a big ESR, out of range. Not sure if these are polymer, but they are the out of specs.

Here the Digikey list.........Red and Cian ones are polymer, the first one is hybrid.. Reds have writen '470' but they are 47.............don't understand it. xDD

I am not sure, but I guess the SD card is for firmware updates.

Regards,
Francesc....

Francesc V. · 07-24-2025, 07:04 AM

I've realized that I was checking voltages with transistors removed from the PCB.............so as long as transistors are in the PCB, voltages come to normal.

So it was normal to have +-30 V in the bases..........when final transistors are there, voltage decreases to +-1V

Francesc V. · 07-17-2025, 02:03 AM

After replacing 7 capacitors and the opened resistor, the Left channel is back to live.

I didn't miss the opportunity to review and recap the other 4 channels from the amp.

I guess that the major problem was the open resistor rather than the old caps.

Regards,
Francesc....

Francesc V. · 07-16-2025, 12:38 AM

Hi:

Thanks for the response. I would say it's equal.........meaning that I am using a signal generator from the phone. i've been using both 1kHz and 440Hz signals in both chanels. So yes............in first picture at least they should be equal (ch1 and ch2).

I've been troubleshooting the schema and I've found up to 6 capacitors out of specifications, and more important, an open resistor.

As soon as I have the replacements, I will post the results and also I will gather some signals fom this C505.

Regards,
Francesc....

Francesc V. · 06-15-2025, 01:14 AM

Thanks!!...

Francesc V. · 06-11-2025, 11:46 PM

Thank you all for the responses and your time.

Francesc V. · 06-11-2025, 01:22 PM

These two dots, with a little bit of imagination turns into an 8 (eight)...............so I guess that these resistors might be 18R2 :-)
It makes sense as long as some in the circuit measure 18.4

What do you think?? Do we accept an eight? xDD

Francesc V. · 06-11-2025, 10:45 AM

It belongs to a Schneider Solar Inverter...

Francesc V. · 04-24-2025, 05:20 AM

Finally!!!!, I discovered and fixed the problem.

I was getting a stable 370V in the primary cap, so PFC was working.

Then I started measuring the REF voltage for each of the 431 that are on the PCB. One of them had no voltage in pin1, others 2.5 stable volts.
Then following up neighbors I realized that pin1 was directly connected to a resistor that it should be 820 ohms, but I was getting K ohms............so I've replaced and auto-magically I started getting the expected 3.3V.

Joint between pin 2-3 removed and SMPS switches on normally.
...

Francesc V. · 04-23-2025, 01:59 PM

Thanks!!! That was the most valuable tip so far :-) I will write it somewhere........shorten FPO to turn on smps whatever it takes :-)

By grounding FPO pin to GND (shorted pins 2-3 in the supervisor) the SMPS turns on.

I had just time to measure secondary voltages before my wife started shouting, however I see secondary STABLE voltages (stable but wrong).

In the 3.3 rail I have a stable but WRONG 9.2 V
5V, -12V and 12V rails are stable and with the RIGHT voltage.

With a secondary stable voltages, I guess there is nothing wrong in...

Francesc V. · 04-20-2025, 03:47 AM

Not sure if I am going in the right direction, but my problem is this -41V I am reading in one of the legs of C515, which is base of Q523.

By removing Q515 from the circuit, this -41V turns into milivolts.

Vbe in "removed Q515", measured from R525 and R535 is 1.3V which tells me that transistor is switched on and that's the reason I am having the wrong voltage above.
In addition, Vbe in Q513 is 0.2mV which tells me that that transistor is closed.

So, not sure if both transistors should be on and both voltages will make that in...

Francesc V. · 04-18-2025, 06:18 AM

FPO pin goes high when powering on the SMPS (4.3V) and remains the same (maybe decreases some milivolts) when pressing PSON to switch on the SMPS.

I put loads in every rail (3.3, 5V, 12V). 40W bulb with a switch.

Momentary voltages when switching on are 4.3, 3 and 11............... so I guess that for some reason there is over-voltage in the 3.3 rail and the supervisor protects the SMPS (I measure 4.3V, then decreasing in pin 5 from GR8313)

Regards,
Francesc....

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