Posts: 909
Threads: 117
Joined: Jun 2007
Hello! Make sure the signal-generator you are using is "accurate". You can check it if you own a "digital tuner" type AM portable battery type radio that has tuning steps in 10 kc increments for receiving stations via "crystal controlled" tuning. Set the test radio (that has crystal controlled tuning capabilities) near your RF generator, and make sure the RF generator is actually "calibrated" for the exact frequencies you are "peaking" the tuning points on the vintage tube receiver you just restored. Make sure you get 455 KC exact ( 2nd harmonic is 910 kc) etc. Peak your IF cans first for max audio on proper exact 455 kc,. Then, set your oscillator adjustments on the "tuning condenser" for proper tracking of stations across the dial. Sometimes, vintage type RF generators are "off" on their dialscale readings, and need to be adjusted for proper accuracy. The very best way to make sure the RF gen is "spot-on",.. is by feeding its signal into either a digital type "frequency-counter"direct, or better yet, use a much less expensive hand-held type Radio with AM & Shortwave Bands "crystal-controlled" receiver that covers all the spectrum to make sure your actually injecting a "spot on" signal reference into the radio you are working on. Since your radio was working before you tried to adjust it, seems logical to me that your RF generator you are trusting is way-out of alignment itself?
I recently had found a bad solder connection on the broadcast antenna transformer of my 42-355. I wouldn't mention it except that it re-occured under similar circumstances. I was trying to fine tune(with a metal screwdriver !?!). I think the noise generated by the screwdriver contacting the chassis area caused the shaky connection to open again(pardon my terminology). I had originally found the bad connection by poking around with a wooden skewer but, had a hard time re-solding it in a tight area. This time, I removed the coil completely, so that I could more effectively re-solder the fragile coil wire. I suppose this probably is irrelevant to the 40-180 above, but I thought it was worthy of mention.
1st thanks everyone for the help.Yes, have had bad solder joints, and yes my gen is off. I have a DVM with a freq counter so I have been checking it every time. So I got back 810 but thats it.
I HAVE A DEFINITE PROBLEM IN ONE SECTION. WHO CAN HELP??
2nd step on tuning, 18Mc on SW. My gen can do 15M. I get it on another radio that has SW. Nice loud wine from across the work bench. HERE IS THE PROBLEM. I CAN get that signal on the 40-180 at 15M but it is soooo weak. I literally hang the signal generator's loop antenna on the SW antenna on the 40-180. I try to adjust the 21A tuning condenser like directions say, tune to second peak. I AM LUCK if I get the first Peak in weak with volume all the way up. THIS I THINK IS MY PROBLEM. What gives?????
NO second peak, first one weak with antenna right on radio antenna.
I scrubbed all condensors, checked all new wires, caps are good, resistors are good, right up to the 1232 tube. CHecked for continuity at band switch, checked for ground on chassis to variable tuning condensor, good. Wires from tuning condensor to small coil in chassis good. What am I missing????
Get 1st step in tuning good. 455kc, 2nd IF can peaks, 1st IF can also has peak on 30, and 30B really makes little difference.
Swapped out 7C6 and 7B7 and 1232 NO difference. 7B7 swap made 810 quite again so switched it back to original.
I also swapped in new wire for SW antenna above chassis in case.
STUCK STUCK STUCK, NO second peak at 15Mc on SW band. WHat gives? thank you for any help. Joe
