[TechAssist] Re: Rca CTC 111 Brightness Problem?
- From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 12 Apr 2004 17:23:50 -0400
Several CTC111 files here:
1.Excess brightness/ retrace lines.
Open C120 (33mfd@250V) located front of flyback.
2. May come on bright, bloomed raster, retrace, may shut down.
Shorted spark gap assy on CRT board. Remove as test. Part# 146169
3. Comes on with bright picture.
Usually bad Q703 "brightness ref transistor" # 3474, use NTE159.
(U700 luma IC can cause also)
4. Hum, or bands in picture.
Weak main filter cap C105 (800mfd) mounted at side. #150728.
But:
I'm leaning to a weak CRT that may have a partial short, and the extra
current during bright scenes is pushing it over. I've seen the Zeniths
do this with a focus grid short in the CRT.
Phil Bader
John & Sharon Mikowich wrote:
>Make: RCA
>Chassis: CTC111B
>
>Hi Everyone;
>
> Got this one in the shop that when you turn the contrast &
>brightness to max. you get a white band in the picture that is flashing
>or jumping rapidly. If you turn the brightness or contrast down this
>will go away until you get a scene with a lot of white in & it will
>happen again. I have seen this on these chassis before, but i can't
>remember what causes this, it's been a long while. Check the usual caps,
>v measurements on the outputs can't seen anything out of the ordinary.
>Any help with this would be appreciated !
>
>Thank You in Advance;
>
>John Mikowich
>East Side Tv.
>
>
>
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--
Philip Bader
Jan Phyl TV Inc. (estab. 1976)
3420 Recker Hwy. Winter Haven, Fl. 33880
Fax (863) 299-8821
email: tjanphyl@xxxxxxxxxxxxxxx
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