Earthquake powerhouse d2 part identification.

[rhempz01]

One was an unknown capacitor and the other an unknown resistor, but may have not been the correct components for these locations. The amplifier Powers up fine just has no audio I believe it is beacuse of this curcuit.

 

[rhempz01]

Entire board.

 

[Perry Babin]

They are both capacitors. It appears that they are C38 and C39. See attached.

 

[rhempz01]

Ok I replaced them with the proper capacitors yet the amplifier still.does not run correctly. I checked all the outputs. It seems like my drive isn't right, with the recitifiers installed?

 

[rhempz01]

Drive with recifiers.

 

[Perry Babin]

If you reduce the 12v supply voltage, does the drive get more like you'd expect?

Do you have proper drive out of the 3525?

 

[rhempz01]

The amplifier with the recifiers just, attempts to power up draws about 5amps and cycles, so I pulled the recifiers. All the output drive is present on the sg3525, in and output looks good on the mic4424

 

[rhempz01]

Sg3525 11&14

 

[rhempz01]

Power supply drive

 

[Perry Babin]

Was the 4080 in the circuit (don't pull it yet)?

 

[rhempz01]

Yes

 

[rhempz01]

Yes

 

[Perry Babin]

Connect a pulldown resistor (wire to 100k will work) between the gate and source legs for one FET in each of the 4 banks. Pull the 4080 and confirm that you read that resistor value (including the gate resistor value, for some) at all FET locations.

If you do, power up the amp without the 4080.

Does it power up?

Does the amp have any DC across the speaker terminals?

Does it have any DC on any speaker terminals, referenced to ground?

 

[rhempz01]

Resistor reads true on all banks. Yes it Powers up without the 4080 in curcuit. Voltage across speaker terminal is .047vdc

 

[Perry Babin]

Do you have another 4080 on hand?

 

[rhempz01]

Yes

 

[Perry Babin]

I'm assuming that you already checked the outputs.

You could try installing it if the other one wasn't a new one.

Remove the resistors before installing the IC.

 

[Perry Babin]

See also 17.

I'm assuming that you reinstalled the rectifiers to see if it would power up without the 4080.

 

[rhempz01]

Yes I did, it does power up without the 4080 in curcuit. Also I have removed all the output transistors and retested them, they are originals and possibly damaged so I'm replacing them.
I going to use the irf3710zpbf. (Ordered them)

 

[rhempz01]

Q7-Q8-Q7R have the following voltages at the pads:
1(g) 5.318vdc
2(d) 80.1vdc
3(s) 5.732vdc
Q?(g) 12.31vdc
Q11(d) 5.726
Q8A(s) 000.0vdc
The other side of outputs correspond to these and are identical.