RetiredHAL said:
Hi, Sarma, I use the B+ 320 to test 400V working, 600/1000v test rated caps and use a B+ 40V (lucky I found that) to test lower rated caps. Problem is not final output (6V6G) -- I can inject 555 variable frequency square wave into Pick Up (phono) setting and not have squeal -- but in mixer/IF/detector or auto gain cct as problem is very faint reception but squeal (not 50HZ motorboating) when I turn up volume.
A solid state radio in a beautiful 1947 cabinet without the rich sound of valves is not acceptable.
Cheers RH
Can you please upload the schematic of your radio in case you have, as that will help easy discussion, sir.
While i will come back on RF diagnosis, (perhaps need replace the Osc-mixer valve-- faintly recollect- whether 6K7 ?)
Can you please upload the schematic of your radio in case you have, as that will help easy discussion, sir.
you may replace the filter caps on AGC feed back path. and also the 6V6G cathode resistor decoupling capacitor. Generally it used to be 25uF/25V
i was suggesting you to use a solid state audio amplifier board like pre assembled TBA810 module to substitute final stage. No issue as you have cleared the audio stage.
Most important appear to be some 1/2 to 1 watt resistors in the screen and suppressor grid ccts, generally above 330, 470 and 680K
hm: which would have eventually opened up. Please have a check.
P S: BTW, i am uploading a tentative schematic for just reference. the valve pin numbers will not tally.i have marked suspected components by arrow. you may check them at similar locations ,with values as marked in your set.