Spontaneous stereo decoding improvement - electrolytics reforming?

[VA1DER]

I have refurbished a couple Realistic STA-77's. One for my son and I loved it so much I got another for myself very recently. One thing in common between both of them was the stereo decoder being a little flaky. I could get the decoder to recognize a stereo station and lock in, but sometimes it took three or four tries (either moving off station and back on, or cycling the mono/stereo switch).

I didn't have the equipment for a proper FM stereo decoder alignment. I was considering a re-cap of mine, but deferred a decision until after an upcoming vacation. In the mean time, I put mine in my bedroom and enjoyed it for a couple days before I left. Partly to give the electrolytics some in-use time to reform. But just before I left it seemed to be getting worse, not better, and I was resigning myself to a recap.

I head off early the next morning on a 12 day vacation.

Yesterday I get back, and the stereo decoding is suddenly rock solid. The difference is marked. It now locks in the first time, every time.

I'm at a bit of a loss to explain it.

All I can think of is capacitor healing, but it was off the entire time I was gone. As I understand the process, electrolytic dielectric reformation requires power. Does a capacitor continue to reform when there is no power? What other difference could sitting unused for 12 days make?

 

[AdamAnt316]

To the best of my knowledge, electrolytic capacitors don't re-form themselves without power applied. I have experienced them re-forming as I used a device, however. When I first tested my circa 1966 Sony TC-100 cassette recorder a few years ago, the mechanism ran but the speaker made little to no sound. I cranked the volume control and let the mechanism run for a few minutes to see what would happen, and slowly but surely the volume of the audio faded in until it hit full blast, and I backed off the volume control. I repeated the test on the TC-100 again a little while ago, and though I thought the caps needed to re-form again, the volume was pretty loud once the song on the tape kicked in, though I did detect it increase a bit after a couple of minutes.
-Adam