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

M

Meatman

Guest
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!
 
"Meatman" <KevinLee33@comcast.net> wrote in message
news:6f199bd8-ac89-41ee-a6e0-6aae02e397cd@y11g2000yqm.googlegroups.com...
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!
Click to expand...
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
 
On Jul 9, 3:43 am, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
"Meatman" <KevinLe...@comcast.net> wrote in message

news:6f199bd8-ac89-41ee-a6e0-6aae02e397cd@y11g2000yqm.googlegroups.com...

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!

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
Click to expand...
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!!!
 
<<
beam limiter sense resistor in ground return gone high ? >>

And where would I locate this little beast...approximately?
 
"Meatman" <KevinLee33@comcast.net> wrote in message
news:3fd25b30-022b-48ff-87c6-4499945051d6@u7g2000yqm.googlegroups.com...
beam limiter sense resistor in ground return gone high ?

And where would I locate this little beast...approximately?
Click to expand...
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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