Vectorlist Archives: Re: Black Widow Video Problem

From: Malcolm Mackenzie <maxstang_at_sbcglobal.net>
Date: Tue Jan 31 2012 - 12:37:41 EST

Thanks Douglas.
The MC1495 at C12 has been socketed and replaced by me. That chip had been socketed before, but the contacts were shorted under the socket. I replaced the socket and chip and that's how I got the video to come up. I haven't replaced C11 as this problem appears to be in the Y channel, but I'll check into it.
As far as I understand the pincushion correction 1495s won't cause this problem. I'll try to piggyback a new one on them to make sure.
One added note. I've noticed that the y-size pot has only a very narrow range of adjustment. Too small and I have y collapse, too large, and y collapse. In the very middle of adjustment the pic stretches out to as it appears in the pictures I posted. Don't know if this helps anyone pinpoint it. -Malcolm

--- On Tue, 1/31/12, Douglas Gauck <douglas@gauck.com> wrote:

From: Douglas Gauck <douglas@gauck.com>
Subject: Re: VECTOR: Black Widow Video Problem
To: vectorlist@vectorlist.org
Date: Tuesday, January 31, 2012, 5:49 AM

The caps are just sauce for the goose; I'd say the next likely cause is one of the MC1495Ls... at C12. I'm not up to speed on how the others (A/B11 and A/B12) providing X and Y correction factor in.

On Jan 30, 2012, at 11:19 PM, Maxstang wrote:

> Thanks for the reply. TL082s have been checked and one replaced with no change. Voltages are good, but I haven't replaced the caps yet.
>
>
> On Jan 30, 2012, at 8:09 PM, Douglas Gauck wrote:
>
>> TL082 at D10 and/or D/E12?
>>
>> Also check the +/-15v and 6.8 volt supplies, and maybe give them new caps?
>>
>>
>> On Jan 30, 2012, at 8:42 PM, Malcolm MacKenzie wrote:
>>
>>> Hi all. I've been working on a dead BW board and now have it at least showing video, but it's still distorted. AVG chip and socket, and vector RAM and socket are good. Anybody seen this before? It almost looks like vertical fold over and the image does expand and contract along the y axis. Self test video is similarly distorted but I don't get any reported errors other than pokey problems. Any input is appreciated. -Malcolm
>>>
>>> Photos are here:
>>>
>>> http://i122.photobucket.com/albums/o263/maxstang289/IMG_2612.jpg
>>>
>>> http://i122.photobucket.com/albums/o263/maxstang289/IMG_2611.jpg
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