Sugden PowerSupply problems.

I have been having some issues with my Sugden A21a Int amp recently that have made listening to it practically impossible.

My problem is that whenever there is a voltage drop of 1 volt or more in the house (appliance turning on) the Power Supply makes a clicking sound and the Amp shuts off for about 10 seconds.

I have checked the house wiring and it all seems to be within spec. The local PoCo considers anything up to an 8 volt drop within spec.

I have spoken to a couple of electrical engineers who suggest the problem could be a marginal power supply in the amp. Their recommendation was to hookup a scope to the Power Rail and watch for ripple. They suspect it is a bad Filter Capacitor.

Just wondering if anyone here has run into anything similar or has any ideas before I take it in and start spending lots of money getting it repaired. I have already taken it in once and they could find nothing wrong with it, however I doubt that this is something they checked and they have very stable power at the repair shop.

Thanks for any input,

-Invictive