[TechAssist] fix RCA F26041DG, CTC157C no vertical: line only
- From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Thu, 24 Jun 2004 14:02:56 -0400
I kept returning to Q4501 with good input, no output...
Found open trace between Q4501 emitter to SMD resistor R4505 (510K).
Cured.
Probably the fine trace was eaten from cap leakage.
Phil Bader
Phil Bader wrote:
>Avisual check showed cap leakage stain on the main center chassis behind
>the vert IC.
>I changed caps C133k, 220mfd@35v , C164: 100@25V.
>In the vert section, leaking C53K: 470@25V and C502K: 220@35V.
>Washed the area.
>No vertical at all. Just a line, has audio.
>Replaced the LA7831.
>LA7831 has volts on pin 5,8, so it has good Vcc source.
>Checked a 3.9 meg R4512, ok
>I get a good sawtooth at input to Q4501 "vert sawtooth" transistor's
>base. Nothing out the emitter. Can't see how it's stopping it.
>Transistor seems OK.
> Traces seem OK.
>I don't have anything on file for this oldie.
>phil Bader
>
>
>
--
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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