Quote:
Originally Posted by Phil Nelson
If you read that article, you'll see this photo showing what was inside a couple of my electrolytic cans:
The two on the left might have worked. At least, the electrolytic paste inside them might still be somewhat operational. The one on the right is totally dried up, crumbling, and shrunken -- like a fossil. The insides are garbage. If I had powered up the set without monitoring the current draw, etc., and that cap was shorted, I might have burned up the power transformer.
It's risky to leave them in place without at least doing some testing. For some people, testing means turning the TV on and holding your hand on the can to see if it burns you. A slightly more scientific way is to monitor the amount of current drawn by the TV and pull the plug if it spikes above what is normal. You can also disconnect those capacitors and test them individually under the right voltage, or even try to "re-form" them by gradually increasing the voltage and carefully monitoring current. In my experience, even electrolytics that appear to "re-form" after a while, may not be reliable for indefinite service. They may fail at any time without warning, and possibly cause damage when they go bye-bye.
I often replace all of the electrolytics because then I am sure they'll be reliable, and I don't have to sit around wondering if my TV is going to go up in smoke. Other people like to re-use every old electrolytic if humanly possible; they understand the risk and don't mind taking it.
Only you can decide how much risk you can tolerate and how you intend to use the TV. If it's going to be a "daily driver," you may want to err on the side of caution. If it's something you'll only play for a few minutes a couple of times a year, to show off to guests, maybe leaving the old electrolytics alone isn't such a big deal.
Phil Nelson |
This is like it is..... But if you already have an old set like your ctc7 and it
comes on and works, you have run it for a few hours and it's ok, then you
may want to slowly replace parts. Replacing stuff that explodes, causes
smoke, or burns out stuff that can't be replaced is a good idea.....
Start with power supply capacitors, work your way to all electrolytics....
Eventually you can replace most of the caps, people here have lists
of types of caps in specific sets that almost always will fail, do them.
But keep in mind there are many many posts here that begin "I recapped
my set and now......" Wiring mistakes, worse new parts choices than the
originals, etc.... Best idea is to do the power supply, then make sure the set
works. Do some other section, then make sure the set works.... etc....
And when yer done, remember there will be a buncha stuff you can't replace
cause it just ain't available....
With a 1969ish kinda cutoff, most stuff earlier than that should have the
electrolytics replaced, there are some safety caps in later sets that are
known trouble, but earlier stuff, 1950's 1940's age is working against ya-
There is too much of a chance of bad failure....
You should have fun, and be careful.