Re: Asteroids DAC question

The second paragraph mentions including that in the process. :) Always
install sockets for an IC, that way if it fails again, you can replace
it easily. It also allows you to put the chip back in easily if it
turns out to not be the problem.

Chad

----- Original Message Follows -----
> 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.

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Received on Mon Sep 12 11:30:12 2005