Kenwood – KA4020 amplifier – cd input problem


This amplifier had problems with the CD input.
No or very bad sound, so first thing i thought about.. Maybe the input selector switch ?


Hooked my scope to the output of the amp ( and mediaplayer connected to the CD input ) only 1 channel gave some output signal..


When I was turning around the selector rotorary knob several times, we got some results, 2 channels are working.


So it’s time to clean the selector switch, but then the switch has be removed.


The module & switch have been removed, as you can see it was a little bit dusty..


To get inside the switch, the back must be bended open.


The swaps after they have been used.. a bit dirty..

Final test

Connected a cd-player to the amp, and played some sine wave sounds to test the output, everyhting looks fine.


New switch for my stock

I searched for new switched for this amp, but I couldn’t find them.