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Re: ProDev DDT16
Steven Hirsch wrote:
I recently built one of these from a parts kit purchased several years
ago. Unfortunately, it doesn't work. My assembly skills are expert
level and I've checked the board over under a magnifier several times
for bad/unsoldered connections. The ROM verifies against a known-good
binary image. Haven't tried this on the PALs yet.
Symptoms: Regardless of slot, entering Cn00G simply hangs the host
computer. The monitor sign-on never appears. I've tried both a Rom 1
and Rom 3 IIGS with no success.
When I dump the slot ROM in the Apple monitor things look correct, so I
don't think the bus interface chips are bad. If I had to guess, it
seems to head south when the CPU bank register is changed.
Does anyone have a suggestion on where to start debugging? I posted on
the A2RetroSystems message board, but I don't think anyone hangs out there.
Quick followup question:
Are there any hobby-type device programmers that can handle the 74S571 and
74S287 PROM devices used on the DDT boards?
I have the PAL covered, but neither my Needhams or Willem programmer appear to
support any DIP PROMs. Are these things tricky to program?
Steve