Restoration Commences on 1947 RCA Victor 721TCS

[Electronic M]

Originally Posted by JohnCT

I think you're assuming members of this forum haven't tried this. I won't speak for any other old timer here, but I have tried it as I mentioned in an earlier comment. What I discovered was that it was hit or miss, and therefore a waste of time when your name goes on a repair. Your example, although very interesting, won't sway me at all.

The Andrea I'm working on has a lot more hours than yours (I'd guess it's well over a hundred twenty five hours since February) and 5 of the cans are still good operating fine, but history tells me that they're on bonus time. Using my own TV as an example, two cans were dead immediately, and two failed some 20-30 plus hours after it was running perfectly. The remaining 5 are still running fine at over a hundred hours. They're still coming out.

Sure, you can have capacitors work after 70 or more years, but proving a capacitor can work at 70 years and proving a capacitor can work for 15 hours a week for the next 10 years is another thing entirely.

I mentioned earlier that I'm restoring an 1850s reed organ melodeon. The leather exhauster is still working, but if don't replace the leather, how long will my wife be able to play the melodeon before the leather tears? 10 hours, 100 hours? Maybe she'll never put enough hours on it, but I'm replacing the leather anyway. Once this melodeon is finished, I don't want to ever take it apart again.

That's the point we're trying to make on this subject.

John

+1
I've also reformed and vetted lytics with my Heathkit and watched them fail after dozzens of hours of operation.

I've seen TVs and radios run on original caps and even keep a few that way as shelf queens that rarely get powered. Though even that isn't common since if I power on a display set and it dies on me it could be an embarrassment, and even if it isn't I rather feel confident I can grab anything off my shelf and run it as if I just bought it new without worry.

I put enough hours on my sets to go through certain tubes multiple times. Anything that will help put the next repair farther out into the future and let me tackle repairing something else or let me live my life away from the bench is worth doing.

[Penthode]

Originally Posted by Electronic M

+1
I've also reformed and vetted lytics with my Heathkit and watched them fail after dozzens of hours of operation.

Well I have seen a bunch fail in service. And many have not passed the reforming process and test before putting into service. You have not explained what your criterion is. Instead you trash my observations.

And as as this to me is purely a hobby, if the component fails in service, it provides further enjoyment pulling the thing apart to service it because it is my hobby.

Maybe some of us should stop to reflect and chill out.

[Electronic M]

Originally Posted by Penthode

Well I have seen a bunch fail in service. And many have not passed the reforming process and test before putting into service. You have not explained what your criterion is. Instead you trash my observations.

And as as this to me is purely a hobby, if the component fails in service, it provides further enjoyment pulling the thing apart to service it because it is my hobby.

Maybe some of us should stop to reflect and chill out.

The process is simple: unsolder positive lead(s) of capacitor connect cap to Heathkit C3, check capacitance and if not open check leakage indication on tester at 50V if good select next higher range,if bad wait 2 minutes for signs of improvement if no change in reading or improvement stops change capacitor, if leakage drops to acceptible select higher voltage test range. If a capacitor tests as having acceptible leakage at full working voltage it gets ran in set for several hours and checked for temperature and possibly leakage again later.

Any more than this is well in excess of my patience, and after doing this process for a few years worth of restos I have stopped as I have come to the conclusion that it is a complete waste of my time over changing all capacitors of a type I know are prone to failure....on any chassis mount lytics once the positive is unhooked it is quicker to solder in a new part, the new parts are cheaper than the time I spend on a reforming, and the guarantee that a new production part isn't going to take out unobtainium for better than 25 years is worth more to me than original parts. I'm keeping the original tube circuits in and not shit canning them to install a flat screen and I usually keep the original removed caps in a bag with the set with a copy of the schematic and enough documentation that any future historian could analyze the original design and parts and put it back to stock if they wanted. That is as original as a working set has to be for me.