K8077 Auto turn on

Kits Audio Hi Fi Projects
1

Hi,

I built the K8077, did the test on pg 22 (all measurements where more or less ok) and everything works fine, except for the auto turn on. I tried this feature on different sources (cd player, computer, tape-out of an amp) but it doesn’t work.

Where do I have to start?

Regards,

Nicolas

2

Check if D1 and ZD2 are correctly mounted and correct value.
Check if +5V arrives at pin 5 of IC3 when a signal is applied at the input.
Check if pin2 of IC3 receives +5V.
If all this is the case, return µ-controller for inspection/exchange.