POSSIBLE CAMBRIDGE AUDIO 650A FAULT...

[aml74]

Anybody???

 

[andrewebling]

Sorry to resurrect a very old post, but I came across this thread while researching...

I have this exact fault with my Cambridge Audio 540a amp - the right speaker cuts out intermittently, but the issue is resolved temporarily by switching to another input and back again.

Does anyone have any suggestions? I'm wondering if one of the internal connections in one of the switching relays (which I hear clicking when switching inputs) has become intermittent.

 

[Gray]

...I'm wondering if one of the internal connections in one of the switching relays (which I hear clicking when switching inputs) has become intermittent.

That seems quite likely.
You could measure relay coil voltages and compare a good with your suspect input - just to confirm that the intermittent relay is being fully energised.
If so, hopefully you can obtain and fit a replacement.

 

[andrewebling]

That seems quite likely.
You could measure relay coil voltages and compare a good with your suspect input - just to confirm that the intermittent relay is being fully energised.
If so, hopefully you can obtain and fit a replacement.

Thank you. After going further down the "how to repair an audio amplifier" research rabbit hole, it seems the speaker protection relays are prime suspects and sometimes these are even replaced pre-emptively when these amps are repaired.

Are the speaker protection relays cycled when switching sources on these amps?

As I have tools, a soldering iron, and a (long dormant) electronics degree, I thought I'd have a crack at a DIY repair.

 

[Gray]

Are the speaker protection relays cycled when switching sources on these amps?

I very much doubt it.
And if the protection relay was playing up, it wouldn't only ever be affecting just the one input.
However, in view of what you've said about them being a common problem, it might make sense to replace the protection relay as well - and arguably all others (though, "If it ain't broke....").
...depends how easy the job looks 🧐
Good luck.

 

[shadders]

Sorry to resurrect a very old post, but I came across this thread while researching...

I have this exact fault with my Cambridge Audio 540a amp - the right speaker cuts out intermittently, but the issue is resolved temporarily by switching to another input and back again.

Does anyone have any suggestions? I'm wondering if one of the internal connections in one of the switching relays (which I hear clicking when switching inputs) has become intermittent.

Hi,
I have this issue on my CA650A Azur amplifier, so i moved it to surround sound duty.

It does seem to be the relays switching the inputs, and changing input seems to clear for a while, and it either recurs later when listening, or resolves for all the time the amplifier is in use. Have not bothered to open the amp up to repair.

Regards,
Shadders.