March 9, 20224 yr i have a vm3 5.2kva solar inverter, that doesn't star from battery. its main s.p.s was burnt, with the help of the service manual available on the powerforum.co , i repaired the main s.p.s butt it doesn't turn on yet from, although IT TURNS ON FROM SOLAR AND GRID POWER but shows WARNING 32. for that i tried to reflash its firmware but it gets fail. I found that there is NO INPUT TO BOTH REGULATORS 78MO5G AND 7912C. what can be the problem.
March 10, 20224 yr 7 hours ago, Wasim said: its main s.p.s was burnt, with the help of the service manual available on the powerforum.co , i repaired the main s.p.s butt it doesn't turn on yet from, although IT TURNS ON FROM SOLAR AND GRID POWE That makes no sense to me. The main power supply is needed to power the processor on the control board; without that, nothing much happens. Quote but shows WARNING 32. for that i tried to reflash its firmware but it gets fail. If the -12 V rail isn't working, then comms won't be working, so that could explain the warning 32 (comms fail from removable display to DSP). [ Edit: It would also explain why the update failed; you need comms to be able to re-flash the DSP, or indeed the removable display, from poor memory. It's probably not a good idea to perform firmware updates when the hardware, especially the power supply, isn't proven to be fully working. ] Quote I found that there is NO INPUT TO BOTH REGULATORS 78MO5G AND 7912C. I can't see how the processor gets power without power at the input to the 78M05 voltage regulator. There is a very strong conformal coating on these boards, and the lead-free solder seems to build a ferocious oxide layer as well, so it can be hard to get a good connection to anything on the board. If you can see good +5 V at the processor board (using the gold plated pins), then there must be power to the 78M05 regulator. But check for -12 V on the processor board as well; you may have a separate fault there. If there really is no power to the input of the regulator, then it has to be something like an open circuit diode, shorted regulator input, shorted smoothing capacitor, or open circuit "transformer". These should all be straightforward to check, but make sure you are getting a good connection with your multimeter probes. After the repair, be sure to replace the conformal coating that you had to scrape off in places, so the board remains resistant to corrosion and other problems from moisture and dust. Edited March 10, 20224 yr by Coulomb
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