Amp power switch problem

[michaelgb 1]

Not sure if this is a sign of something serious or not , but on my Harmon Kardon intergrated amp (HK680) i have a problem with the power switch.

Most of the time the on/off power switch works fine , i switch it on , hear a click sound, it powers on and sounds like it should,  but sometimes i flip the switch, lights go on ok but i get no click sound and silence follows.

When this happens i need to hit the button a number of times till the amp clicks on, 

Any ideas ? i hope shes not on the way out.

Edited February 12 by michaelgb

[michaelgb 1]

Found this on a polish hifi forum, same amp, same problem . Looks like he fixed it by checking and re-soldering all the connections of the little black box pictured near the bottom of the thread. What is that black box, a relay ?

https://www.elektroda.pl/rtvforum/topic2847698.html

[wizmax 141]

Hi Michael

The service manual can be downloaded here:-

https://www.hifiengine.com/manual_library/harman-kardon/hk680.shtml

You will need to register with hifi engine but its free and they do not contact you.

The schematic of the power board is on page 15 and the parts list on page 23.

Using the Polish photos and page 15, yes it is a relay. 

[toprepairman 26]

Hi Robin. No doubt see you Sunday?

[michaelgb 1]

Many thanks