21-10-2015, 03:51 PM
(21-10-2015, 03:33 PM)ppppenguin Wrote: With the set switched off and the caps thoroughly discharged you can measure between the tags of the smoothing cap with a resistance meter. This will tell you if there are resistors present and working.
These 2 resistors work fairly hard for a living and get hot. They are good candidates for failing. Assuming that one or both have failed the real question is whether they died of old age or due to a fault. For example if the capacitor C25 on Terry's circuit clip is leaky then the audio output valve will take excessive current which could easily kill either or both of those resistors. Can also damage the valve and the output transformer.
I'm a bit confused here. Are you saying the H.T. supply from one tag on the H.T. cap passes through to the other tag inside the can itself through an internal resistor?
Basically as I recall, on the top of the first can is three tags. One I think is a ground. One of the tags has a definite feed from the rectifier cathode. It shows a good 400 volts D.C. The tag opposite has no voltage showing but it supplies H.T. to the set. In fact only one terminal of the can shows a voltage.
The tag that shows no voltage at all has no supply from the cathode of the rectifier.
I think I need to get all of this absolutely clear before going ahead.
