Cambridge Audio A640 repair

My Cambridge Audio A640 integrated amplifier has been suffering from drop-outs and clicks for years. I discovered that it got better after switching sources a couple of times, which forces the output relays to open and close. This led me to believe that there could be a bad contact in the output relays.

I ordered a couple of new relays, put them in and the problem is fixed! Crystal clear sound again!

Overview of the main board and -encircled- the output board


Detailed view of the output board and indication of the connections of the two relays. There is one relay for each channel. I didn't take the trouble of getting the board out, as that required disconnecting and unmounting too many other things. Just take off the speaker connectors to loosen the board somewhat and replace the relays from below the output board.


The new relays: Omron G2RL-2, 12V coil, 8A switching current, 250V/AC switching voltage