ok it would go into protect then removed driver board and would power up fine so had another driver board from another hifonics amp, identical to the original, installed it and would power up fine, then all of a sudden it would blow my 10 amp fuse when powering up checked output transistors in board and legs 2 and 3 on right bank of 6 would read 0 Ohms in circuit found the 2nd fet to be bad other 5 check good but what could cause excessive current draw even if the fets and driverboard are removed, ive removed 6 of the fets, and it powers up fine but seems to draw more than normal current, when i install just the driver board back in circuit it goes back into protect
Are you sure that you don't have solder bridges between the pads for the outputs or the driver board?
Transistors on the other side of the amp can make it appear that there is a short on the side with no transistors.
ok im going to remove other 6 fets and see, they are reading like the others in circuit ill post results
solder pads check good on all 12 places after removing all outputs , going to see if goes into protect with driver board installed and check those 6 fets
replaced outputs the bank of outputs on speaker terminal side 1st fet reads near 0 ohms in circuit but good out of circuit it is Q204
Between legs 2and 3 , I'll double check to see if others read funny, could it be the driver board? I could remove it and check the fets again?
That transistor is in parallel with other (adjacent) transistors. I'd suspect broken traces or pulled vias if it reads shorted and the others do not.
Vias are the copper feed-throughs that connect the traces on one side of the board to the traces on the other side of the board.
Are either of the other two shorted? If not, there may be an open connection between the drive circuit and the gate of the FET that was preventing the FETs from switching off.
Are either of the other two shorted? If not, there may be an open connection between the drive circuit and the gate of the FET that was preventing the FETs from switching off.
Are all 3 OK out of the circuit?
Did you check the ones on the other side?
Many times, when you have parallel transistors, you can find the shorted one by measuring the resistance from the gate to the drain. The shorted one will read lower resistance than the other ones.
Did you check the ones on the other side?
Many times, when you have parallel transistors, you can find the shorted one by measuring the resistance from the gate to the drain. The shorted one will read lower resistance than the other ones.
the other side checks fine , here is Q203 of the bank what it reads out of circuit, will post other 2 as well
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