GTIL2 power production degradation

[Wizzard]

Hello.
I have system with GTIL2 2000w inverter, and recently its power production start to degrade. On time line like 2 weeks its maximum production decreased from 1650W to just 1200 and continue. Decrease rate looks linear and constant.
I tried off/on and different setting with or without limiter, its always same maximum, so it looks like hardware problem.
My guess based on how it happen that some capcitor is dying, but may be someone have expirienced same problem and know better where problem is? Or may be could provide advice what it could be?

 

[Wizzard]

I switch it off for a night and at morning when i switch it on it produce its usual full power but degrade again later, also strange thing that on continius load it provide 150-200W more for first 1-2minutes

 

[Wizzard]

Aaaand another "step" down today now its 650W max, looks some wierd thing, which i unable to find anything like that. So i will disassemble it today and try to check at least visually.

 

[Wizzard]

Ok problem look fixed.
After i create post here i remember that some time ago i saw videos on youtube from german speaking guy about this inverter, where he quite deeply inspect this inverter. So i search again and it was Christian from canal https://www.youtube.com/@DerKanal
I contact with him, and he provided suggestion that problem is in shunt resistors. So i disassemble inverter and check it first, visually all looked good without any problem, so i use thermal imager to check and found out that this place of borad have high temperature

When i send this image to Christian he answered that it's exactly the place where shunt resistor places from back side.
So i check this resistors and it looked ok. But on Cyprus there is no such detail in stock anywhere, only option to order it and wait 10-20 days... So after some thinking i decided to better solder this shunts to contact pads, because there was quite few solder.
Wihtout much hope i assemble everything back and since that it properly work for 3 days already.
So thanks to Christian for help and maybe someone find this info useful.
P.S.
After some time manufacturer also answered to me in mail and also suggest to check this resistors together with 4 other: