Restoration Commences on 1947 RCA Victor 721TCS

[Penthode]

Originally Posted by Electronic M

.... your experience leads me to have completely different feelings about vintage capacitors than you, and whats left of my understanding of college engineering reliability statistics tells me I shouldn't change my mind.

Well I am a professional Electronics Engineer. I know what I have read and been told. In a professional sense, keeping old capacitors like this is wrong. But heck this is a hobby about extreme vintage televisions. The owners of this set put it away in 1960 and forgot about it because by 1960 it was if not obsolete, quaintly old fashioned and dated.

For historical reasons, I want to keep as much originality to it consistent with it working reasonably reliably. Perhaps even the 60 years it sat unused help preserve the electrolytics? Who knows? All I can say is that the capacitors show the correct leakage and capacity and the set will operate for a dozen hours at a time without getting warm.

As for the other components, so long a the picture and sound remain excellent as the set currently does, what is the issue

From purely a hobby perspective and as I wish to keep this set and because I am technically inclined, I am very happy that I have such a good working set with much of its originality maintained
I am going to keep the set running and will update this column as the set approaches 100 hours on time.

Meanwhile I gave an old 630TS someone tried to repair and gave up on. I am going to give it a go and try to clean up the wiring.

[init4fun]

Tis a sad fate indeed suffered by all too many rectifiers .....


I trust my x wife 100 times more than I trust any electrolytic cap that's as old as I am

[Penthode]

Originally Posted by init4fun

Tis a sad fate indeed suffered by all too many rectifiers .....


I trust my x wife 100 times more than I trust any electrolytic cap that's as old as I am

The reason you trust your wife more is because you are kinder to her than your electrolytics! If you read earlier thru the thread, the patient and proper reforming of the dielectric is the key. How long running time will it take to convince you the capacitors are okay?

[init4fun]

Originally Posted by Penthode

The reason you trust your wife more is because you are kinder to her than your electrolytics! If you read earlier thru the thread, the patient and proper reforming of the dielectric is the key. How long running time will it take to convince you the capacitors are okay?

I was more or less joking with you , if you noticed I said "my x wife" , no kinder there my friend .

Kinda like your "dry" joke , I guess humor & electrolytics just don't mix


and yes , I am interested in how long the reformed caps live .

[Eric H]

I wish I could find the pictures I have of some old caps I took apart.

When I say rotted I mean exactly that, if you unroll the foil there are areas where the aluminum has been eaten away, with gaps in the foil, there are often lumps from the crystals that have formed that leave dents on the paper insulator, I would guess it's these dents, if they get bad enough, that press through the insulator and cause shorts. I have seen several caps where the connecting leads between the foil and the lugs have corroded completely in two causing an open.

And of course I have opened some 40's caps up to find they are still wet and pristine inside, but that is the exception. I imagine the type of storage and the length of time they have been inactive plays a part.

I'm not trying to be contrary, it's an interesting project to try minimal repairs, but I think it is a gamble that they will continue to work, not a big deal since this is a hobby and if it craps out it's not a big issue.

I'm an amateur hobbyist, so it's usually easier for me to just change them and be done with it rather than wonder if that odd little problem I'm having is being caused by an old capacitor.