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-   -   muntz tv/ceramic disc caps (http://www.videokarma.org/showthread.php?t=256351)

radio nut 10-31-2012 07:12 PM

muntz tv/ceramic disc caps
 
The Muntz tv I got running for a friend has been a pain. I put caps and electro's in it and got it going. Then a chassis mount resistor shorted to ground and killed the high voltage plus the rectifier tube really did not like that although the colors were neat!.

Ok, fixed that and moved the set from the workshop in the barn to the garage while the cabinet was being restored.
Turned the set on and it buzzed really loud through the speaker. Shorted tube.... alright then I just was not impressed with the picture itself....to gray and gray and not really very black and white.

Checked voltages and in the IF they were "off"
Well keep in mind that the resistors that were out of tolerance were changed.
I could think of nothing else beside ceramic disc caps. I want to make sure that I do not have to tear this out of the cabinet again so I just shot gun replaced those and then the picture was crisper and had the kind of black and white image I was used too.
Now as far as I have read here on this site it seems to me that most people believe that ceramics dont fail.

Are we getting to the age now where they might or is this probably cheap parts from the factory?

Oh, since then I have once again lost high voltage to the crt and traced the problem to (what are they called?) a hard flat square that has three tiny resistors and three caps in it.

So now I am making one of those on a terminal strip and will mount that this weekend.
One thing after another with this set!!!!

mstaton 10-31-2012 07:31 PM

They are couplates. Not sure if the spelling is correct.

ctc17 10-31-2012 08:15 PM

I have recapped entire sets with ceramic disk caps, they work fine. Only thing with them is they drift with temperature so if its a critical cap I put it under the chassis away from heat.
Those couplets do go bad. you can rebuild them with discrete parts.

radio nut 10-31-2012 09:26 PM

Quote:

Originally Posted by ctc17 (Post 3052897)
I have recapped entire sets with ceramic disk caps, they work fine. Only thing with them is they drift with temperature so if its a critical cap I put it under the chassis away from heat.
Those couplets do go bad. you can rebuild them with discrete parts.

You only used ceramics?

ctc17 10-31-2012 09:54 PM

Quote:

Originally Posted by radio nut (Post 3052901)
You only used ceramics?

No, depends on the set, the values etc. If its a set I really dont care about Ill stick disks in there. If its something like a 630ts I use the red NTE caps.

I recapped a late 60s all tube panasonic color set with a semi weak crt with all disks and it works great.

Have never had any issues, I know its not a popular thing to do but they work fine so long as you keep them away from heat sources.

radio nut 11-04-2012 05:22 PM

1 Attachment(s)
Well lets see, my home made couplet did the trick and the high voltage and picture came back up. Then the sound went out and a tube went to air.
Replaced that and all seems good.

radio nut 11-04-2012 05:27 PM

2 Attachment(s)
more pics. I am pretty sure the base is home made. The wood is not the same on the sides

miniman82 11-04-2012 06:11 PM

I like the base, compliments the set very well.

Kevin Kuehn 11-04-2012 09:34 PM

Looks nice. :thmbsp:


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