Re: Asteroids DAC question

When replacing them consider soldering in sockets so when they fail again
they're easy to pull out

----- Original Message -----
From: <tower@gis.net>
To: <vectorlist@vectorlist.org>
Sent: Monday, September 12, 2005 3:57 PM
Subject: RE: VECTOR: Asteroids DAC question

>
> I have an AD board that is down right now... the signal on one of the X
> or Y lines, forget which since it's been months, is way too low. It was
> something like -2v to +3v in range when I measured it with my cheap DMM.
> It's supposed to be +12v to -12v, right? IIRC, I picked up some DACs
> and another IC that were the likely culprit but have been scared to try
> the desoldering/resoldering required.
>
> I guess my question is, should I try the other IC first? The plan was
> to desolder and swap in a new one, installing SIP sockets in the
> process.
>
> Chad
>
> ----- Original Message Follows -----
> > owner-vectorlist@vectorlist.org wrote:
> > > Is there an easy way to know if the AD561J DAC(s) on an asteroids
> > > (or similar type) board need to be replaced? Like is there a common
> > > symptom of when they fail versus say something else in that same
> > > circuit area?
> > >
> > > Do the DACs tend to completely fail, or partially fail?
> > >
> >
> > Scott,
> >
> > On the Asteroids boards I've seen with bad DAC's ( 4 total, so I'm no
> > expert) the video is still there but corrupt. And the corrupt video
> > was "repeatably" corrupt: corrupt in the same area and in the same
> > way. When put into test mode the grid was out of whack but the
> > picture was clear and solid. Depending on which DAC was bad, the
> > horizontal or vertical lines looked like dots. The diagonal lines
> > look jagged.
> >
> >
> >
> > Sean McLachlan Salt Lake City, Utah
> > rgvac@classi-find.net Video Game n00b since 2001
> >
> > ----------------------------------------------------------------------
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> > or problems to chris@westnet.com
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Received on Mon Sep 12 11:06:51 2005