Hello,
I'm trying to fix a solar inverter that has failed due to suspected high voltage.
I'd really appreciate if you would be able to help me identify these parts so I can order more. - I've googled for hours and have come to a dead end.

h3121441 (Optocoupler?)

bv-art12816-001
(1231 FALCO) (HF transformer?)

SMD 6525 ( Schottky diode?) rest on diode test = pin 1+ ,pin 2- = 0.294v pin 3+, pin 2- = 0.294

SMD R28 ( transistor?)


Pictures attached, let me know if any other pictures would be helpfull.

Thanks for your time,

Carl

 

Hi,

Unfortunately it is very hard to identify some parts unless you can see the schematic. If you care to draw a schematic of the circuit people might be able to help more. If the part number does not turn up anything that's the next try. I know it takes a lot of work to trace out the circuits and make sure you get them right, but that's the way reverse engineering is. It takes a lot of time. If there is only one part you cant find that is bad, you end up buying a new converter anyway unfortunately.
If you do make a schematic, it should be clearly drawn so as to make it easy to read. Using the schematic and picture of all the parts it may be possible to determine what they are even without part numbers.

 

Thanks MrAI, I had a feeling that could be my next step.
I've emailed the manufacture with high hopes they will send me a schematic but as I know from past experience, its extremely unlikely!

 

Hello,
I'm trying to fix a solar inverter that has failed due to suspected high voltage.

Is there any visual indication at all? It wouldn't surprise me if there was an over-voltage protection built into the device somewhere. Maybe show us where the suspected high voltage was applied.

I'd put your chances of getting the schematic from the manufacturer at darn near zero. But have you searched for a service manual, or maybe someone else's repair blog? Sometimes it's amazing what you can find. And sometimes there's nothing.

 

Yeah I think so... Have a look at the picture I've attached - what do you think?

The maximum current that could have come from the attached array would have been 8 - 10 amp. The maximum voltage can get to just below 950vdc - which is under the maximum rated voltage for the MOSFETS but only by 50volts. The Schottky is rated at 1200V.

There are some burn marks on a SMD capacitor near by too... it leads me to believe it could have also been a moisture / condensation problem.

The manufacture had been going for 20 years but declared bankrupt not long after getting problems with their inverters. Although they are very well built, I do think putting some MOSFETS rated at a 1000v in a 900v system is a little brave!!


I've done loads of searching but there aren't any blogs or repair help online... once I figure this one out, I'll definitley be doing a repair guide as there are 1000's of these inverters with this problem.

 

Well, MOSFETs are testable. It's tedious to remove and test components at random but if you can narrow your focus it helps.

An oscilloscope would be helpful for testing, as would a known-good unit to test against. That'd be my first step if I couldn't find a service manual.