[TechAssist] Re: Rca PTV P46770CK PTK169PAAS chassis No contrast update
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 28 Apr 2004 18:05:05 -0400
Al,
I have seen the following three components cause that type of symptom. I
might suggest you replace them even if they check good:
CR2901 (part# 198589)
C2909 (part# 190542)
C1409 (part# 215555) (located off pin 16 of U1401)
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxx
geminitv@xxxxxxx
www.geminicomputertvsecurityalarms.com
----- Original Message -----
From: "al m" <ampm@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, April 28, 2004 5:46 PM
Subject: [TechAssist] Rca PTV P46770CK PTK169PAAS chassis No contrast update
> this PTV the contrast will not adjust. I have found that if I disconnect
the
> Beam limit transistor the contrast adjusts.checked all parts in that
circuit
> and all check OK. Now the big question. Does anyone know what waveform
> should be on the line that comes from the high voltage Regulator board to
> the main board on E25? I have checked the voltages on the transistors and
> the transformer waveform looks good on pin 2. It must have something to do
> with the amplitude of the signal going back to the beam circuit. Can weak
> picture tubes cause this to happen? Have very little experience with these
> beam circuits. Thanks.
> Al Marquardt
> ampm@xxxxxxx
> Al Marquardt Electronic Repair
> 206 W Main
> Girardville Pa. 17935
>
>
>
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