820-00138-05 dont turn on

[Dozer]

hello.

the board is not turning on, no liquid to see.

i found a short to GND on PPBUS_G3H, I pulled the F7140/41, short to gnd still on buckconverter side

i pulled the u7100, still the same, so i pulled Q7135 and no short anymore. I ordered new q7135 and after solder in no short anymore, i put bacj the fuses but the board dont turn on

Now i see i forgot to put back the u7100, its still pulled out but the short is back, after pulling again the q7135 no short anymore

the pulled out new q7135 is shorted completly


so i need some help what can damage the q7135? the u7100 is still pulled out.

 

[2informaticos]

Yeah, you left high-side MOSFET Q7130 with Gate floating on air.
Don't do this ever again!!!

However, I suppose it was shorted before; but you only check for short to ground, on Q7135.
Be sure to solder ALL removed components and check for shorts BEFORE powering up the board...

 

[JohnB8812]

Replace U7100, Q7130, Q7135, and Q7155 all at the same time ONLY if removing them relieves your short.

 

[Dozer]

ok, thank you all for your help.

I put the u7100 back and the fuses in place, put in another Q7135 and its working fine everything.

Are you suggest to replace now the u7100, q7130 and q7155 as well ? is it needfull?

 

[JohnB8812]

If it works now, then no. But for future reference, you want to replace all at once.

 

[Dozer]

ok, thanks a lot for your help