24-04-2012, 12:08 PM
Hi Joe,
Good to see that some progress is being made. By what you've reported above, sounds as though something is going seriously non-linear as that pre-set is adjusted: sounds like a faulty semi-conductor device to me; could be a faulty diode in the O/P transistors bias-setting chain or possibly one of the O/P transistors. With that type of device failure, it may not show itself on an ohms test, so replacing the suspect component(s) may be the best diagnostic approach to take. I'd start by replacing the diodes.
Having said all that, there is some guess-work there, since I haven't seen the cct. diagram.
Al.
Good to see that some progress is being made. By what you've reported above, sounds as though something is going seriously non-linear as that pre-set is adjusted: sounds like a faulty semi-conductor device to me; could be a faulty diode in the O/P transistors bias-setting chain or possibly one of the O/P transistors. With that type of device failure, it may not show itself on an ohms test, so replacing the suspect component(s) may be the best diagnostic approach to take. I'd start by replacing the diodes.
Having said all that, there is some guess-work there, since I haven't seen the cct. diagram.
Al.
