by Sal Thu Oct 21, 2010 4:04 pm
Greg,
The best way to check the quad cap is to connect a high voltage power supply set at or slightly below the rated voltage to the capacitor (disconnected from the circuit in the amp) and with a milliamp meter in series to measure the current at the capacitor rated voltage. If the capacitor is good it should pull a few milliamps maximum per section and not get warm. Once that is done, you must, I repeat must discharge the capacitor and measure the capacitance of each section.
Actually, you can measure the capacitance of each section before you put B+ to it to measure current.
And lastly, if you have a ESR meter, you can check that also.
Hope this helps.
Sal
PS: If you don't have a high voltage power supply you can use the power supply in your amp. Be very careful as there are lethal voltages under the chassis.