It's possible you may still have a shorted capacitor sucking down your voltage, a defective resistor or a connection not in place. If I get time I'll look at the schematic and see if I can suggest something.
bob Rosengarten
Clarksville OH
: Am trying to repair a Philco Model 37-630.
: Tubes light and radio has played briefly twice.
: All tubes are good.
: Have replaced all electrolytic and tubular caps and some resistors in power supply.
: Results of checking voltages per schematic:
: The screen grid voltage to 6K7G rf tube, 6A8G det.-osc, and 6k7 IF amp reads 15V but should be 75V.
: All other voltages are nornal.
: I am still doing lots of reading on theory and repair.
: Any ideas on where I might check from here?
: Any help would be appreciated.
You could also have an open in one of the plate ckts. If this happens, the screen tries to act as a plate, drawing high current, when it is designed to draw little. Hope this helps!
Check or replace the screen load resistor, especially
if the supply voltage on the input side of it is correct.
Also replace the screen bypass capacitor. It may be
leaking badly. Make sure the tube is biased correctly
on the grid. If the plate voltage is higher than it
should be, you can suspect that the tube is bad regardless
of what a tube checker says.
Hi Dave- I know its a year later, but wondering if you
had any luck yet. Try unplugging all three tubes- the sreen voltage should be at or near plate voltage. If so, replace one tube at a time to find faulty stage. If not, is there a separate resistor in power supply for screen voltage? No schematic here. Good luck!
- Bruce
Hi Dave - I know its a year later but wondering if you had any luck. Try unplugging all three tubes, the screen voltages should be at or near plate voltages.
If so, replace one tube at a time to see which stage
is defective, drawing down screen voltage.
If any tube causes drop, problem is in a component common to all three stages. Sorry, no schematic here.
Good luck - Bruce