Posted by Isao Asakura on January 21, 2003 at 21:29:11:
In Reply to: Sansui 500A Biasing posted by Robert Johnson on January 18, 2003 at 20:52:34:
500A operates with the fixed bias output stage. Once it's set, you should not need to adjust the pots. Most likely, your 500A has bad coupling caps. In a few minutes after you turn the power on, bad coupling caps will start reducing (goes to less negative voltage) the bias voltage, and output tubes become red hot. If this is your case, you need replacing those coupling caps.
: This is the stereo receiver from about 1964 both of the outside power tubes (EL84s) are running very hot on both transformers. Does anybody have an idea of how the bias is adjusted on this unit?
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