Re: Battlezone repair question

Joel Rosenzweig wrote:

> >Look for 'constant' data or address lines (this takes experience)
>
> Do you mean stuck bits high or low? Or something else?

yep, stuck high or low, or sticking in the grey zone (no logic).

>
> >Look for funny data buffers (LS245's)
>
> Same question here, too.

Basically, make sure in=out.

>
> >the Self test can run with only the RAM, the uppermost ROM (addresswise)
> and
> >functional hardware (vector etc). Try taking out all unnecessary CPU ROM in
> case you have
> >a shorted address or data line on one of them. AFAIK, the self test screen
> will even come
> >up find if you take off the AUX board (but you will have a mathbox error).
>
> Makes we wonder if I should simply shotgun the whole CPU section and replace
> everything from the CPU through the RAM and ROM. There's not that many
> components there to worry about. I just hate pulling out so many chips
> because there's always the chance of wrecking a trace on the board. I use a
> desoldering station, but sometimes I've still managed to lift a trace when
> Murphy is lurking.

I would seriously replace the LS245's first. Is your reset pin pulsing repeatedly?

If those buffers done work right, nothing will, they are the connection between
the CPU and the 'outside' hardware.

>
> You've given me some encouragement. Thanks!
>
> Ok, one last question. I don't know about you guys, but I find it hard to
> troubleshoot a game when it is installed in the cabinet. Certainly, that's
> a great test bed, but it's way too cramped in there for me. Sometimes I've
> bothered to wire up an entire test harness just to debug a game. Do you
> find that you do the same, or are you using some technique that makes it
> easy to do your testing in the cabinet?

If you have a game that is dead then it is much easier to pull it out and fix
it on the bench. In Atari's case, you only need +5V and a +12V for the reset circuit.
All other supplies are for sound output amplification or vector output.
---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Wed Jan 12 14:30:39 2000