Re: Re: Star Wars shaky video

http://s32.photobucket.com/albums/d39/golfg60gti/?sc=1&multi=1&addtype=local&media=image

Here are some shots, one each of the x and y outputs on a scope and another
of the grid test screen on the monitor. You can see there are evenly spaced
steps that seems to scroll up the screen.
----- Original Message -----
From: "simon" <simonjhanlon@btopenworld.com>
To: <vectorlist@vectorlist.org>
Sent: Sunday, July 09, 2006 10:40 AM
Subject: Re: VECTOR: Re: VECTOR: Star Wars shaky video

> Yes I'm thinking its a bad dac also, I have other working sets that play
> fine so the fault is on the avg board not the machine. I hooked up my
> scope to the output of 7a and can see the noise there so the fault is
> probably there or the dac
> ----- Original Message -----
> From: "peter jones" <highwayman2000@mail.ru>
> To: <vectorlist@vectorlist.org>
> Sent: Sunday, July 09, 2006 3:47 AM
> Subject: VECTOR: Re: VECTOR: Star Wars shaky video
>
>
>>
>> -----Original Message-----
>> From: "simon" <simonjhanlon@btopenworld.com>
>> To: <vectorlist@vectorlist.org>
>> Date: Sat, 8 Jul 2006 19:36:41 +0100
>> Subject: VECTOR: Star Wars shaky video
>>
>>> Hi Guys
>>> I have been repairing a Star wars pcb that I bought off ebay. I dead so
>>> I removed the avg board and self test started to work. I checked the avg
>>> board and found some damaged traces, repaired them and the board now
>>> passes all test and plays fine except the video is shaky. In self test
>>> you can see small steps in the vertical lines on the grid screen. I
>>> guess its a bad cap somewhere in the Y section but I can't find it. Has
>>> anyone had this fault before? I have checked all the caps have both legs
>>> still intact, no noise on the +15 or -15 lines.
>>>
>> could be power - you should recap anything that old anyway.
>> that said, i assume your using a testbench psu that should flatline like
>> a deadman.
>>
>> last time i saw a fault like that it turned out to be a bad dac, dac
>> failures seem common on atari pcb's judging by the number i have with
>> sockets fitted or missing chips.
>>
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>>
>
>
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Received on Sun Jul 9 08:38:30 2006