Re: Tempest FROZEN, passes self test

> This boardset passes the self test (no bad RAM beeps, no error codes), but
> when switched to normal play mode, it freezes up (no X or Y board output
> (flatline on scope), solid player select LEDs). I've swapped CPU's with a
> known good one, and swapped ROMs with a known good set. I've tried various
> dipswitch settings (started with factory, then to free play, etc.), so I
> know it's not the dipswitches themselves or their settings. I've also
> swapped the aux board with a known good one.
>
> (Other *obvious* info: checked & verified voltages, clocks, dipswitches.
> Other good boardsets work in the same cab).
>
> I'm thinking the freeze mode is stuck active, but know nothing about it.
> Any ideas, suggestions, or advice? Have scope, will fix. Thanks in advance!

Do you see any activity on the bus when its frozen? Is the watchdog firing?
(check the various irq/nmi lines). What are all the address bus lines doing?
Data bus lines?

On things like this I usually poke around with the scope and look for things
out of the ordinary. I run down the processor. I check various address
decoders. All sorts of stuff like that. It doesn't take long (and sometimes
really doesn't help), but its found the bad bus transceiver, etc..

What does the board do without the math box plugged in?

(I'm sure some of the real Tempest experts will pipe up with the instant
answer, though.. :)

Kurt

This signature file is temporary until the previous file (currently
on free floating metal oxide mixed with disk head fragments) is found
on some non-readable backup tape.

Kurt Mahan
kmahan@novell.com
Received on Tue Dec 23 07:29:28 1997