Quote:
Originally Posted by Boobtubeman
Thanks old1625
Both radios are identical in chassis and have both had FULL RECAPS...
One just performs better than the other under IDENTICAL circumstances 
Both radios do well when it comes to SW bands but one radio seems to do poorly on the lower side of the AM dial. Not to mention one of these radios came off EBAY and when i opened it, i found someone had been in it before me and tinkered a bit, so i am presuming they might have turned a few variable caps.. Just thought perhaps a good tune- up might help
Steve |
I once was visiting a young man, son of some of my brother's neighbors, who was starting out in antique radio resto. He was working on a large console, and had managed competently to recap the whole thing. But unfortunately someone had fidddled around with this radio before, and apparently had tightened up every loose screw they could find, so all the peakable circuits were way off kilter. The kid had no signal generator. And I didn't have mine with me. So I asked him to open up a well-working AM table radio and set it up with either an isolation transformer or find some blocking caps somewhere. I tuned the second radio to a strong local station and turned the volume down. I proximity-injected the IF signal from the final IF transformer secondary into the various stages of the old chassis, starting from the detector and working back up the signal path to the converter, peaking each IF transformer as I went. The next thing we knew the old chassis started working on its own account, pulling in a station from Boston. Inside of a half hour we had it all peaked, tweaked and stuffed back into the console cabinet it came from.
After the IF stages are peaked and aligned at the standard frequency for the set the sensitivity and station positioning relative to the #s at at the low end of the dial are usually dealt with by adjusting the inductance of the coils of each RF stage and the local oscillator by moving the ferrite slugs in the coils. The upper end positioning and sensitivity are usually adjusted by diddling the trimmer capacitors across the main tuning capacitors in the gang. One has to go back and forth between the low and high end and keep correcting until all is where it should be. It takes practice, and sometimes one runs into a set that does not have movable slugs in the coils, and a loop antenna instead of an RF input tank coil, in which case low-end tweaking can be much trickier. Usually one starts by making sure the local oscillator is tuned so that the stations fall on the dial where they are supposed to be.
I'm sure there is someone in your area that can probably lay hands on the radio and make it well if you feel you're in over your head.