Audiobahn 8000t

[mike49504]

Im working on this amp. So far ive replaced all the power supply fets(irfz44)
Ive replaced all the 100 ohm gate resistors. Ive replaced the fet drivers.
Replaced all the outputs in the amp.

The reason is everything was smoked in the amp.

When i try powering it up the power supply fets on the side circled get red hot within 2 secs wondering where i go from here?

[djQUAN]

remove the fets, power up the amp and remote and check if the gates have square waves (or about 6V with a DMM from gate to ground)

[Perry Babin]

That's a photo of an 8005. Are you working on the 8005 or the one in the photo below?

I agree, you need to check the gate drive signal. If the amp isn't drawing excess current, you may be able to check it with the FETs in the circuit (transistors tightly clamped to the heatsink). The voltage at the gate should be very near the voltage on pins 9 and 10 of the 494.

What did you use as subs for the drivers?

[mike49504]

one side of the fets the ones not getting hot from gate to ground 5.03 volts

The side the fets get red hot gate to ground 0.00 volts

[mike49504]

i used the original part number a1023 i found a couple new ones i had laying around

[Perry Babin]

Are you getting 5v on both pins 9 and 10 on the 494?

[mike49504]

4.98 volts on pins 9 and 10 of the 494

[Perry Babin]

That would seem to indicate that you have...

a shorted a1023
an open diode (parallel with the a1023)
a broken connection between the 494 and the gate resistors

[mike49504]

ok i replaced the 494 with one i had laying around now pins 9 and 10 read 0 volts

[Perry Babin]

Post the DC voltage on all 16 pins:


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16: