K8060 some problems

Kits Audio Hi Fi Projects
1

Hi,
I recently built this kit.
It worked perfectly until a fault occurred with my pre-amp which caused various components on the amp board to fail (R20,T5,D2,R1) With these components replaced and also TIP142 + TIP147 I powered the unit without any load, set the bias to 12.3mv. I carried out some further checks which revealed the following voltage of 8v across sk1 + sk2 (input), -23.3v across speaker connection. I would like conformation before reconnecting this to pre-amp and speaker or should I replace any other component(s). I don’t believe that there should be a negative voltage from the +ve speaker connection.

Regards
JBM

2

There should only be a couple of mV at the speaker output.
There is definately still a problem with the amp, most likely in the output stage.
Basically, we’d recommend to replace all semiconductors (transistors and diodes), since one defective part can take out a bunch of other parts.