Quote:
Originally Posted by JohnCT
If it's going to be a shelf queen and get run for 10 minutes several times a year, you may not have a problem.
I restored a 51 TV earlier this year and did it one part at a time just to bone up on tube troubleshooting. Once done, it was shotgunned (well, not fully done).
This TV has nine electro cans, and two were bad on first power up, one taking out the 5U4, the other taking out a 6X4. I pulled them and restuffed them, and soldiered on.
While working on the sound section, another can that had previously checked fine and had run cool for several hours decided to make itself known. A slight change in the picture followed by a hiss told me another can had enough. Where it was running cool for several hours beforehand, it now was *very* hot. The fact that it was also drooling like a 5 year old kid with a mouth full of Sour Gummy Worms was another clue..
So far, 4 cans restuffed and the other 5 will be done before final assembly. The paper caps that are running fine will also be replaced before final assembly and alignment.
John
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I have running four other RCA sets from the late 40's. Two 8T243's (I sold one) an 8TC271 and a 9TC275. The 8T243s and the 9TC271 were dormant and never plugged in and I simply reformed the capacitors and use them regularly with no problem. I have had the 8T243 for 50 years this year (yep I was given it in 1970. I have used it for 50 years since on its original electrolytics. The 9TC275 on the other hand sat in a damp basement and the seller pugged it in until he said he saw smoke. I looked at the electrolytics and two cans were ruined and a third survived. I have a CTC5N color and it has all the original electrolytics. A CTC11 with high hours had bad electrolytics and i ended up replacing them all.
The 721TS I plan to keep and I want to retain as much of t original as possible. And my past reference is more than 50 years of restoring electronic equipment. I see that the Sprague and Mallory capacitors have an unduly bad reputation.
If the electrolytics lasts 100 hours and I do not abuse it I expect it will last the remainder of my lifetime. Would you agree? I would also venture it will outlast a modern replacement if I was to install one.
The 721TS has been running 20 hours now and still running fine...