K8060 damaged - help required please

Kits Audio Hi Fi Projects
1

Hello all

My K8060 was assembled and working fine, and then I did a silly thing and screwed a screw into my toroidal transformer, shorting out a winding- while the ampifier was running. I have repaired the transformer and it gives a perfect 29V AC x 2. The K8060 shows no visible sign of damage but it now shows:

  1. Loud hum irrespective of input.
  2. No bias adjustment possible.
    The board shows +40V DC and -40V DC where it should, also the +9V DC is fine and the LED lights. I have changed the big smoothing caps and the rectifying diodes test OK. Can someone please suggest:
  3. What other diagnostics can I do on the board? (I have a multimeter but not a scope)
  4. What I may have damaged - I suspect I introduced >>40V to the board?

Many thanks
Dave J

2

In such a case, we replace both power and driver transistors.

3

Thanks for the reply.
Could you confirm the transistors please in terms of “Txx” ref in the manual and/or transistor model numbers?
Cheers

4

Replace T3…T8.