Kenwood Kac-8104D Problem

[Perry Babin]

With the outputs out of the circuit, does the amp blow a 10 amp fuse or go into protect?

 

[bigpun4fubu]

still goes into protect

 

[Perry Babin]

Is there still a pulse of DC across the speaker terminals?

 

[bigpun4fubu]

yes jumps all over the scale

 

[Perry Babin]

Did it blow the 10 amp fuse?

What's 'all over the scale'? You need to be as precise as possible.

 

[bigpun4fubu]

didnt blow fuse, goes from 15v to 22v to the mv range and so on

 

[Perry Babin]

Make sure that there are absolutely no solder bridges between the solder pads where you removed the output transistors.

Check between the pads with your meter to confirm that there are no shorts between the pads.

 

[bigpun4fubu]

all pads were free of bridges

 

[Perry Babin]

Solder a bridge between pins 6 and 7 of IC32. Do you still get the pulse on the output?

 

[bigpun4fubu]

yes 15 v then drops to mv scale

 

[Perry Babin]

Check the following transistors in-circuit to see if any are shorted.

Q410
Q405
Q404
Q408
Q415
Q409

 

[bigpun4fubu]

Q415 legs 1-2 shorted Q410 is one of the outputs that was removed Q409 good Q408 good Q404 good Q405 good

 

[Perry Babin]

Q410 should have been Q401.

Desolder Q415 and check it out of the board.

 

[bigpun4fubu]

Q401 is good should i remove the solder bridge on ic32?

 

[bigpun4fubu]

Q415 checks good out of circuit

 

[Perry Babin]

Either Q408 or Q409 could make Q415 look shorted. Recheck those.

Do you still read a short across the pads for Q415?

 

[bigpun4fubu]

no sir

 

[bigpun4fubu]

ill check those after work

 

[bigpun4fubu]

im getting 331 ohms on legs 1-2 on Q409

 

[bigpun4fubu]

408 checks good out of circuit, should i remove 409?