IC Replacement


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IC Replacement

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glen65
New User

Oct 1, 2008, 2:54 AM

Post #1 of 10 (2079 views)
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IC Replacement	Can't Post

Hello
I am working with an RCA model 32F530T TV.
The chassis number is ATC113-CD4.
I am having some vertical issues and found that
freezing the main 56 pin IC will change the way
it acts, so apparently the chip is failing thermally.
The Chip is a TB1253CN. I am having trouble
locating it but the TB1253AN can be found pretty
easily and at a pretty good price. So the question
is, can I use the AN in place of the CN?
Thanks

rrobor
Veteran

Oct 1, 2008, 6:32 AM

Post #2 of 10 (2072 views)
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Re: [glen65] IC Replacement [In reply to]	Can't Post

Usually the first letter is the series or in mosfet B is for buffered, but a searh in google there are 3 of thesa A C and D. Personally I would not take the risk. Ihe jungle is only supplying a timing pulse so I would not jump to conclusions,. Freezing the thing may well cause change and jungles causing vertical issues is almost as rare as hens teeth.

Paulpablo
Enthusiast

Oct 1, 2008, 9:25 PM

Post #3 of 10 (2056 views)
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Re: [glen65] IC Replacement [In reply to]	Can't Post

What kind of vertical problem are you having with that set?

glen65
New User

Oct 1, 2008, 11:31 PM

Post #4 of 10 (2053 views)
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Re: [Paulpablo] IC Replacement [In reply to]	Can't Post

Thanks for the replies,
It looks like I’m going to need to back up bit,
first some history. The set came in and wouldn’t start.
It would only make a loud noise from the supply
when plugged in. I replaced a shorted HOT and bad
flyback which got the set running. When I first
started the set it ran fine for awhile then started
to do something strange at the top of the screen
(see pic).

It’s a bit like vertical fold over but doesn’t
seem to change or warp the images at the top of the screen.
For lack of a better term I’ll call it a bar. The bottom
edge of this bar isn’t even visible for about 1 hour.
Then slowly advances downward until it get to
be about 1-2 inches in height. I noticed that when I
handle or reposition the brown and black wires
that come from the vertical section and run to the yoke that it will
make the bar change size.

Using a solid background here’s what the set looks
like when first turned on

Here it is 1 hour later.

I tried replacing the vertical output IC along with the
the surrounding electrolytic caps. I also replaced
a 220 ohm flame proof resistor that was burnt in the center.

Any help appreciated,
Thanks

(This post was edited by glen65 on Oct 1, 2008, 11:33 PM)

Paulpablo
Enthusiast

Oct 1, 2008, 11:55 PM

Post #5 of 10 (2050 views)
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Did you use an OEM flyback?

glen65
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Oct 2, 2008, 1:44 AM

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In Reply To

Did you use an OEM flyback?

No I used an HR Diemen Flyback (HR 80295). The original number is 257807. Its my understanding that the flyback has been a common issue on this set so I chose to go with a replacemnt brand.

(This post was edited by glen65 on Oct 2, 2008, 2:12 AM)

rrobor
Veteran

Oct 2, 2008, 9:35 AM

Post #7 of 10 (2031 views)
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Give you odds of 10 to 1 that its not the jungle, the shape of the vertical scan is wrong, its hard to be certain with these pictures but it looks like a bit of foldover which if viewed as a sawtooth waveform, the peak of the wave shape has flattened off suggesting low power from the supply. Im concerned by this 220 ohm FR, are you sure thats correct, what does it feed. The usual in the vertical is 1 fuseable and 2.2 may be the correct value. If the flyback went and took the vertical , if that resistor is in the LT feed to the vertical, you are creating your own issues.

glen65
New User

Oct 2, 2008, 3:05 PM

Post #8 of 10 (2025 views)
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It’s resistor “R09” in the vertical section (close to the vertcal IC). I don’t have the service manual to confirm this, but I read that it is supposed to be a 220 ohm 2 watt resistor or RCA part number 247674, but maybe this info is wrong.

Paulpablo
Enthusiast

Oct 2, 2008, 6:22 PM

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Re: [glen65] IC Replacement [In reply to]	Can't Post

That chassis has bunch of vertical problems. I will give you a list of parts that I have replaced to repair the set. DFOI,IF01,CF05.

glen65
New User

Oct 2, 2008, 10:16 PM

Post #10 of 10 (2015 views)
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In Reply To

That chassis has bunch of vertical problems. I will give you a list of parts that I have replaced to repair the set. DFOI,IF01,CF05.

All of those have been replaced with no change in operation.

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