10-24-2018, 06:55 PM
I have just re-capped and "re-resistored" my "new" 46-200. It's one of the later iterations with a PM speaker, resistors in place of the field and a few other part substitutions from the earlier production runs.
All is well EXCEPT for the audio. It's distorted at any volume level above low -- as if the AVC isn't working properly. All components in the circuit are new except for the tube.
A several-year-old thread notes a potential cause related to the built-in loop antenna. The loop exhibits continuity just fine and appears to have just two connections -- one to the antenna coil and the other to the RF section of the the tuning capacitor. Do these need to be in any particular order with regard to front and back of the loop? I can't see that it would make any difference, but I'm surprised that the antenna has anything to do with audio distortion at all, so...
Oh -- here's another new post-restoration symptom that may be related: when I remove the external antenna lead from the chassis, reception is improved, even without an antenna wire connected. (The distortion remains, though). In other words, a two inch long chunk of wire outperforms the loop!
Any ideas?
Many thanks,
Craig
Silver Spring, MD
All is well EXCEPT for the audio. It's distorted at any volume level above low -- as if the AVC isn't working properly. All components in the circuit are new except for the tube.
A several-year-old thread notes a potential cause related to the built-in loop antenna. The loop exhibits continuity just fine and appears to have just two connections -- one to the antenna coil and the other to the RF section of the the tuning capacitor. Do these need to be in any particular order with regard to front and back of the loop? I can't see that it would make any difference, but I'm surprised that the antenna has anything to do with audio distortion at all, so...
Oh -- here's another new post-restoration symptom that may be related: when I remove the external antenna lead from the chassis, reception is improved, even without an antenna wire connected. (The distortion remains, though). In other words, a two inch long chunk of wire outperforms the loop!
Any ideas?
Many thanks,
Craig
Silver Spring, MD
