Antique Radios Forum

This is the temporary home of the Antique Radio Forums while a new server to host it is being found. You will have to register here to post. Please Note: None of these topics will be preserved when the original forums are back.
HomeCalendarFAQSearchMemberlistUsergroupsRegisterLog in

Share | 

 Help with a Hallicafters S-20 R

Go down 

Posts : 2
Join date : 2010-10-21
Location : Tapppahannock, VA (Washington State Native)

PostSubject: Help with a Hallicafters S-20 R   Fri Oct 22, 2010 10:29 am

I have been restoring a Hallicrafters S-20R. The cabinet is 9/10. I have replaced all of the by-pass capacitors, filter caps and many resistors. The unit appeared to be working but needed a good alignment. I got the IF working well and the local oscillator on all the bands except the BC band. (BC has a bad trimmer on the LO coil.) The radio was receiving some shortwave broadcast stations but nothing else. By ear, I tuned the input to the 6SK7 RF amp but the output had no affect. Metering the input to the mixer I found almost no signal. It took 100k uV to see anything on the grid of the mixer. I don’t know what it should be but that looked wrong to me. After further investigation I have discovered the wiper on the band select switch for the mixer input is MISSING. No clue as to were or how it became missing. There is no evidence of it having ever been there and take may hours of work to replace it if one could even be found. The switch is buried between the chassis bottom and the RF amp plate tuning capacitors and coils for 4 bands. I had a heck of a time just seeing that it is missing.

Anyone have suggestions for a work around fix? It is a beautiful radio and it would be a shame to dump it.

I have been thinking of RC coupling between the RF plate and mixer grid. What kind of signal voltage should I have on the mixer grid? Any suggestions on component values?

Back to top Go down
View user profile


Posts : 20
Join date : 2010-10-14
Age : 74

PostSubject: Re: Help with a Hallicafters S-20 R   Fri Oct 22, 2010 12:57 pm

This is a second post of the same thing.
Back to top Go down
View user profile
Help with a Hallicafters S-20 R
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
Antique Radios Forum :: Antique Radio Forums :: Antique Radio Discussions-
Jump to: