[Hallicrafters] S-38C dial tracking and AGC

[Craig Roberts]

My thanks to Don Erlich for his thoughts regarding the insufficient AGC action and inaccurate dial tracking on my S-38C.

Regarding the dial tracking, he makes a very good point about IF alignment. I performed the IF alignment with an RF generator and VTVM but noted, at the time, that peaks in output voltage and speaker volume were not coincidental. It is possible that I took the "old-time repair" approach and tweaked for loudness. I'll re-do the alignment tonight. just in case.

With respect to the AGC problem, the IF amp tube could be at fault. My early, perfectly functioning S-38A uses the usual All-American Five 12SK7 in that slot. The later S-38C employs a 12SG7. While I have a pile of 12SK7s, I do not have a spare 12SG7 to substitute in the "troubled" receiver. I've ordered a couple, though, and will make the swap when they arrive.

Again, many thanks to Don.

73,

Craig
W3CRR