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CRT: Brief contrast/brightness prob at start-up.

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Meatman

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Jul 9, 2010, 2:34:17 AM7/9/10
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32" RCA Entertainment Series CRT. Had popping noise w/ no pic or
sound. Replaced HOT and FBT. Now A-OK except: At start-up, every start-
up, contrast/brightness is way low/very dark picture. After 3-5 secs
it corrects and is normal. I even let it run for 30 hrs straight to
see if it would freak-out in other ways. It didn't. Problem is quite
sufferable, but I'd like to chase it down. Ideas? Thanks again!

Arfa Daily

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Jul 9, 2010, 4:43:15 AM7/9/10
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"Meatman" <Kevin...@comcast.net> wrote in message
news:6f199bd8-ac89-41ee...@y11g2000yqm.googlegroups.com...

Wrongly set 'screen' control on your new FBT ? Taking a while for the beam
limiter to assess what's going on and correct for it ? If original FBT was
faulty, beam limiter sense resistor in ground return gone high ?

Arfa

Meatman

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Jul 10, 2010, 2:37:36 AM7/10/10
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On Jul 9, 3:43 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
> "Meatman" <KevinLe...@comcast.net> wrote in message

BTW: RCA MODEL F32450 CHASSIS: ATC113CA1

I just dialed in the FBT by eyeball with it turned on. Tweaked both
settings til I had what I thought was best picture. Then adjusted
from menu settings. Should it be done another way? Everything else
is kosher except for prob described. THX!!!

Meatman

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Jul 10, 2010, 2:45:46 AM7/10/10
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<<
beam limiter sense resistor in ground return gone high ? >>

And where would I locate this little beast...approximately?

Arfa Daily

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Jul 10, 2010, 4:49:16 AM7/10/10
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"Meatman" <Kevin...@comcast.net> wrote in message

news:3fd25b30-022b-48ff...@u7g2000yqm.googlegroups.com...


> <<
> beam limiter sense resistor in ground return gone high ? >>
>
> And where would I locate this little beast...approximately?

The setting of the screen control can be very critical, depending on the
circuitry design, and the condition of the CRT. Usually, there is a point to
measure a voltage on, and a critical voltage to set on that point, using the
control. A service manual will usually be helpful for that. The beam current
sense resistor, assuming that it has one in the position I indicated, is
usually physically quite close to the FBT itself.

Please note though that the observations I am making are general to CRT TV
sets from the last 20 years, and not necessarily specific to your make and
model, which I am not intimately familiar with, it being a U.S. model, and
my practical experience all being with U.K. models. However, that said, the
circuitry design from what I've seen, is generally pretty similar in all but
the front-end low level signal and colour processing circuitry.

Arfa

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