[Raleigh]

I have mostly completed restoring the electronics of a 40-150. It was a mess when I started, with some previous work I had to rip out. I restuffed the electrolytic capacitors, replaced all of the paper caps, most of the mica caps and many resistors. Once I brought it up, it operated well, but it had one odd problem. The frequency shifts abruptly. For example, I would be listening to WPTF in Raleigh at 680 AM. Suddenly the station would go away as if I had tuned to an open place on the dial. I re-tuned, and WPTF would be at about 620 or so on the dial. The same thing seemed to happen with other stations. For example WDOX would shift from 570 to about 530 or so. The sift to lower frequencies would (mostly) not be reversible until the radio had been shut down and started at a later tiime.

This is not a drift, but an abrupt shift in frequency.

When I was working on the chassis, I could often make this downward shift happen by wiggling he tuning condensor, but usually no amount of wiggling would restore to the original frequency of 680. Once the radio is off for a while, the frequency woften starts as it is supposed to be, but sometimes it starts shifted down 20 or 30 KHz.

My question is--does anyone recognize these symptoms? Does it have anything to do with the grommets that isolate the tuning condsensor from the chassis? The grommets all seem to be worn out, allowing the consdensor to be pulled a little out of true by the pulley and tuning cords.

Any advice would be appreciated.