BrianGT amp keeps blowing up

[revell]

Ok my GT kit doesn't want to work
First time I switched V- and V+ accidentally so they blew . Replaced the chips,
then I switched both V- and V+, checked resistance between chip and heatsink: no problem there. But when I turn the power on both secondary fuses (3A) blow and a little blue smoke appears from the pcb

any advice?

[G4ME]

put the blue smoke back in?

reverse the caps?

[kilowattski]

I am sure you blew up more than just the chips. Check the other components like the rectifiers and capacitors. You can't blame Brian because you swapped the positive and negative supplies.

[Peter Daniel]

You have to replace rectifiers.

[revell]

I'm not blaming brian, I just want to get my amp working.
PSU is in separate housing and working fine.
C's mounted correctly (V-: negative lead,PG-: positive lead, V+: positive lead, PG+: negative lead)

Is there a way of checking without turning the power on?

[BrianDonegan]

Capacitance meter...

[karma]

i second that replace all the rectifiers. and look the pcb over
make sure there are no fried traces

i got a few kits and i fried one rectifier pcb. i put the rectifiers backwards buzzz pop

[steenoe]

Ok my GT kit doesn't want to work

Yes it does Sounds like you have a short somewhere. Check all your leads and solderings very carefully, there is a fault in there.
The fault is still there when the fuse blows It can be a little thing like a stray strand on one of your leads. Or a solderbridge.
Compare everything closely to Brians nice building instruction.
Component orientation and so on.
It could also be your solderiron that accidentaly meltet something it wasn't supposed to.
Good luck.

Steen.

[revell]

I found my mistake: somehow V+ is connected to V- on the pcb.
I haven't found a solution yet, no visual solderbridges. but I noticed that heat conducting paste got between the legs of the chip. that shouldn't be a problem right?

[The Shaman]

Originally posted by revell
but I noticed that heat conducting paste got between the legs of the chip. that shouldn't be a problem right?

Depends on the type of compound you're using. If it is the the standard white silicon-based goop it shouldn't be a problem. If you're using a better thermal compound(ie, Arctic Silver, etc) then it may very well be conductive.