Hi,
I have a Westinghouse H303P4 portable the prints here.
http://www.nostalgiaair.org/pagesbymodel...024160.pdf
I have recapped it and replaced the resistors that were out of tolerance. I had one bad tube the 1U5.
The If's were peaked (slugs) to 455kc no problem then I went next in the instructions to do the OSC (C8) at 1615kc feeding the signal into the tuning cap C5 and I cannot pick up a tone at all! The OSC coils read 12 and 2.6 ohms so they look to be ok. What am I missing? Thanks
Eric
Hi,
Check the filament voltage across the 1R5 if it's just a little low it could stop the osc from working. If you have a variac you run the line voltage up a little to see if that gets in going.
You might be on to something, I only get .980 volts on the 1R5 filament. Now I changed out the selenium rectifier and have a 100 ohm 5w ceramic for a dropping resistor if I raise the variac to it's max about 135 ac I get 150vdc (calls for 140v after the rectifier) between R16 and R3 seems like that should be enough but I only get 1.07vdc across pins 1&7.
Now I hooked up a power supply from AES I get 88vdc on the "B" battery and 4.5vdc on the "A" battery and I can adjust the "A" to get 1.4v on 1R5 but still nothing except static? where to go?
Maybe a weak 1R5. Also check the connect to the loop ant.
R-20 is a voltage divider which drops the the B+ down to make the filament. Check it's value they can run hot and change value. If it's ok then play w/that resistor that is in series w/the si diode. Lower the value till the filament is @ 1.5v or so.
GL
Swapped out the 1R5, Put a resistor in parallel and lowered the resistance and increased the filament volts to 1.35V. for some reason I can pick up a tone at 1400 and 2200kc on the signal gen but it will not adjust to the 1615kc with C8.
I re hooked up the DC power supply and I get 1.45V on the filament but reacts the same way. I'm going to pull and recheck the tubes and call it a day this tiny radio is wearing me out!
I just assumed that have the proper voltage or close to at the screen grid and plate of the 1R5. The voltage there is much more forgiving than the filament.