03-10-2023, 06:39 PM
Hello all,
I'm working on a Coronado (Gamble Skogmo) model 527A. The schematic can be found here http://www.nostalgiaair.org/Resources/060/M0007060.htm
I've whittled the trouble list down to one item and I am in need of some guidance. I cannot get the oscillator adjusted. When the tuning gang is completely open at 1720 kHz and the signal generator set at 1720 kHz, I can only hear the modulated signal by tuning the radio to about 1200 kHz. This is with the oscillator trimmer backed all the way out. Since the radio would not tune any stations initially,I don't know if this problem is a preexisting condition or not.
I can tune in the usual stations for my location but they show up about 500kHz low. The radio seems to play well other than the tuning being so far off.
I have substituted an NOS 6A8 and that resulted in no change. I also checked the wire dress against the pictures I took before starting work and they are very close to the pictures. Capacitor C2 was out of tolerance and replaced, but that had no effect.
I'm stumped and can only think of one or two unlikely things that could cause this problem. Any help would be appreciated.
I'm working on a Coronado (Gamble Skogmo) model 527A. The schematic can be found here http://www.nostalgiaair.org/Resources/060/M0007060.htm
I've whittled the trouble list down to one item and I am in need of some guidance. I cannot get the oscillator adjusted. When the tuning gang is completely open at 1720 kHz and the signal generator set at 1720 kHz, I can only hear the modulated signal by tuning the radio to about 1200 kHz. This is with the oscillator trimmer backed all the way out. Since the radio would not tune any stations initially,I don't know if this problem is a preexisting condition or not.
I can tune in the usual stations for my location but they show up about 500kHz low. The radio seems to play well other than the tuning being so far off.
I have substituted an NOS 6A8 and that resulted in no change. I also checked the wire dress against the pictures I took before starting work and they are very close to the pictures. Capacitor C2 was out of tolerance and replaced, but that had no effect.
I'm stumped and can only think of one or two unlikely things that could cause this problem. Any help would be appreciated.
Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.
