RE: Asteroids Troubles...Ram???

I had this kind of case on a Tempest. Turned out to be a bad ROM giving
junk to the CPU (though the ROM test passed). This junk caused the CPU to
go beddy by and the watchdog to bark. Same deal, a short vector flash.

So check all your ROM's, even if they pass self test they still might have a
problem.

David

> -----Original Message-----
> From: owner-vectorlist@mcfeeley.cc.utexas.edu
> [mailto:owner-vectorlist@mcfeeley.cc.utexas.edu]On Behalf Of
> MKDUD@aol.com
> Sent: Thursday, January 21, 1999 8:40 AM
> To: vectorlist@mcfeeley.cc.utexas.edu
> Subject: Asteroids Troubles...Ram???
>
>
> Hello,
>
> I've been trying to repair an Asteroids board, and with the ram
> discussions on the list regaurding Battlezone, I thought I'd
> better ask a
> couple questions.
> First, the board would give me a single low buzz on
> powerup in test mode.
> My original rams were NEC UPD2114LC (have a funny little
> green dot on the
> lower left of the ic). I began replacing ram (using AMD's
> AM9114CPC, brand new
> from Bob Roberts). I went through all 6 rams, installing
> sockets and replacing
> the UPD2114LC's with the AM9114cpc's. As I replaced each one,
> the test tone
> would go high after the new ram was installed (I guess I was
> making progress),
> and I would get a low buzz that the next original ram was bad. After
> installing & socketing 6 brand new rams, I get a continuous
> beeping (beep,
> beep, beep, beep.....) and no more low buzz (I'm guessing the
> new rams are
> passing). When I pull one of the new rams, the high tones
> come back (showing
> the installed rams being good) and I get a low buzz on the
> pulled one. I
> think the beep, beep, beep (with all new rams installed) is
> the watchdog
> tripping, and after the monitor warms up, I see a slight
> vector flash on the
> screen with each beep.
> First, if there is a speed or compatibility difference
> with my new ram,
> could this be causing the "beep beep, beep",....? Has anyone
> used AM9114cpc's
> on an Asteroids board? Are these AM9114's going to work?
> If my ram seems to be fine, (I'm getting no more low
> buzzes, and when I
> pull a newer ram, I get a low buzz ) what should I be
> checking next? Please
> excuse my ignorance, this is my first attempted repair of an
> Asteroids board.
> I do have a good logic probe, and access to a scope. Any
> help or advice would
> be greatly appreciated.
>
> Thanks Very Much,
> Michael Kelley
>
Received on Thu Jan 21 13:18:54 1999