[TechAssist] Re: GE M# 46GW950 CH# CTC169HN - Picture pulses on / off
- From: <myers_tv@xxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sun, 8 Feb 2004 08:55:52 -0500
Thanks Al,
Yes, I have the training manual & the troubleshooting guide. I never thought
about pulling them out, though. I'll pull them out.
I'll try replacing those diodes. I found two of them, but can't find CR7065
in that circuit. Could you mean CR7056?
I pulled the raw B+, as you suggested, and still had audio.
Here's a new glitch. I was just scoping the signal at pin 4 of the chip. The
manual calls for a rather garbled waveform about 2.3V P-P. It is switching
between this waveform, and a Sine wave. It is doing this at a rythmic (about
1Hz) rate. I was starting to suspect the regulator IC, and I may still throw
one in, just for giggles.
Thanks
John Myers
Myers TV Service Since 1984
Alliance, OH
ph 330-821-6545
----- Original Message -----
From: "al m" <ampm@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Saturday, February 07, 2004 8:37 AM
Subject: [TechAssist] Re: GE M# 46GW950 CH# CTC169HN - Picture pulses on /
off
> John do you have a training manual? Check CR7073, CR7058, and C7065.
> Disconnect the raw B+ to the aux board and see if the audio is ok. If it
is
> and the B+ to the aux board is ok then you have a aux board problem. If
you
> need a scan of the trouble shooting for the aux board let me know.
> Al Marquardt
> ampm@xxxxxxx
> Al Marquardt Electronic Repair
> 206 W Main
> Girardville Pa. 17935
> ----- Original Message -----
> From: <myers_tv@xxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Sunday, February 08, 2004 8:17 AM
> Subject: [TechAssist] GE M# 46GW950 CH# CTC169HN - Picture pulses on / off
>
>
> > Hi,
> > This is an early production CTC169HN chassis.
> >
> > I've already replaced the caps & Diodes in the Horizontal output
section,
> & recapped the power supply. I've replaced the AFT Video det & AFT coils.
> >
> > Now, my last problem is that the picture pulses on / off at turn on. If
I
> let it pulse for a minute or two, it'll stop. This is the one I'm having
> trouble with.
> >
> > The power supply on the PTV AUX board is pulsing. The raw B+ that comes
in
> from the main board checks OK.
> >
> > I've replaced Q7051 the turn on transistor, and shorted Q7051 C-E as a
> test.
> >
> > The voltage at U7004 - 4 is running about .4V instead of .89V that is
> called for. The voltages at pin 3 (current sense input), and pin 1 are
right
> on. I've tried heating & cooliing, in hopes of finding a bad cap.
> >
> > I'm hoping that someone has seen this before, and can point me in the
> right direction.
> >
> > Thanks,
> >
> > John Myers
> > Myers TV Service Since 1984
> > Alliance, OH
> > ph 330-821-6545
> >
>
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