CA Azur 640A v2 - need help diagnosing

[deliorix]

Hi everyone,

My Cambridge Audio Azur 640A V2 goes into protection mode immediately after power-on, protection LED flashing 3 times (CAP5: overvoltage/overcurrent). I have a multimeter and oscilloscope for testing and would appreciate guidance on where to focus.

1. Protection triggered with no load:
   • Disconnected all speakers, inputs, and pre-outs – issue persists.
2. Visual inspection:
   • No bulging/leaking capacitors, burnt resistors, or charred PCB traces.
   • Output transistors appear undamaged.

Thanks!

 

[BSST]

Are the attached manuals correct for your amp?

Make sure volume set to minimum.

Confirm power supplies have proper voltages and no excessive ripple.

Look for DC voltage at PA outputs, before protection relays. What do you find?