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From: Chuck on 4 Apr 2006 10:28
On Sun, 2 Apr 2006 18:07:09 -0400, "Retro Depot"
<retrodepot(a)bellnet.ca> wrote:

>First off, I'm new to this group, thanks for taking the time to read this.
>Now, this 35" RCA is driving me nuts and I'm questionning my ability here.
>The problem this set has is as follows. With any input, (rf, composite), the
>video is distorted, I mean, the image has what look like 60 cycle hum bars,
>not moving, just there, couple of inches from top n bottom. It'll lose
>vertical sync sometimes if channel is changed. Chroma either disappears or
>is severely shifted. Skin tones go from normal to almost flourescent green.
>Horizontal width is affected slightly on the right, (1/4 - 1/2" black,
>slight pincushion, not enough to suspect pin circuit though, probably due to
>this irritating problem.) The jungle has been swapped as a result of the
>'shotgun' approach suggested to me, I have the schematic, it's not helping.
>Am I missing something very basic?
>Please help.
>Cheers, Steve
>
Try replacing CR4121 and CR115. Hope this helps. Chuck
From: Steve on 4 Apr 2006 11:06
Thanks for the input Chuck, those were the first diodes suspected, no dice.
The set is on now and I'm monitoring cr8712, (8.2v zener), it's stable at
8.17v. The picture is still shifted to the left, no change when poking
around. Gonna scope the video going into the jungle again to see if I missed
something. I've replaced the sub carrier xtal to no avail.
Cheers, Steve


From: Do Little2 on 4 Apr 2006 11:24

"Jason D." <sparklemagicdust(a)aim.com> wrote in message
news:4431dfc8.436930671(a)news1.on.sympatico.ca...
.........
> > If you study the print of the 169 you will see that the EPROM is not
> > initialized when you plug it in, that doesn't happen until power on.
> > The 503K rock drives the countdown chain, which is needed for H
> > sweep. The EPROM runs off of H sweep. What was happening is
> > that sometimes the oscillator didn't start immediately, and the data
> > from the EPROM to the micro came too late. A 169 will run without
> > an EPROM, but it's in some type of "fallback" mode or something.
>
> Blink, What what??? I thought micro did the job with eeprom not the
> 503KHz? EVEN the micro did have own crystral!? That why ingorance is
> showing! Even I have worked on 169 often, this why I needed the
> training book.

The part of "A 169 will run without an EPROM, but it's in some
type of "fallback" mode or something." is not in the training manual,
as far as I remember. So even a training manual is of no help here!


From: Steve on 4 Apr 2006 11:32
Typo, I meant CR4712 not 8712 sorry.
"Steve" <retrodepot(a)bellnet.ca> wrote in message
news:pVvYf.67828$6Q2.974090(a)weber.videotron.net...
> Thanks for the input Chuck, those were the first diodes suspected, no
dice.
> The set is on now and I'm monitoring cr8712, (8.2v zener), it's stable at
> 8.17v. The picture is still shifted to the left, no change when poking
> around. Gonna scope the video going into the jungle again to see if I
missed
> something. I've replaced the sub carrier xtal to no avail.
> Cheers, Steve
>
>


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