Re: Battlezone problem (Self test)

David Shoemaker wrote:
>
> Has anyone ever disassembled BZ to figure out just what self test is doing?
> I have two boards (as I have said before) that when put into self test
> appear to be starting self test then watchdog out and reset (at about the
> time they should tone once and display data). But both boards run when not
> in test (though no display data).
>

That is a strange one, it is usually the opposite. I have dissassembled
the ST in
battlezone once about a year ago. The reason I did it was because I was
having some
serious problems getting the board to run. It kept giving me bad RAM
tones. But when
I would replace that RAM, it would just indicate that another was bad. I
put the RAM
that I REMOVED from the BZ into a tempest and they were all good!! It
was getting
frustrating so I started to doubt the "integrity" of the RAM tone
program in self test.
Basically the self test goes through these steps...

   Sets up the Stack pointer
   Clears all the RAM
   Tests the RAM a chip at a time, a half byte at a time (since the
2114's are one 4 bits wide)
   tests the ROM
   tests the pokeys
   tests the EAROM.

When I looked at the code for the RAM tests, it seemed very vague then I
ran out of time to work on it.
I decided to go with past experience and just start replacing the
LS245's. Well, it worked. That was the
problem. Flaky 245's... Ugggh.

Hope that rant helped some though?
  jess

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Jess M. Askey            *** Coming Soon - The Game Archive ***
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