[sdiy] PPG Wave 2.3 Boot Problem

Synthusiast synthusiast at gmx.net
Tue Jun 25 20:54:33 CEST 2002

Hi Hermann,

Thank you for your response.

> The battery is indeed unnecessary for booting, although it might be a good
> idea to put one in :-)

Ok, I'll install a Lithium battery soon. :)

> .) reset the 3 DACs on the I/O board

Sometimes all DACs get initialized to 0V and sometimes to 5V.

> .) +5V line doesn't deliver ... you said you checked that, right?

All voltages on the backplane are OK and the voltages on the I/O board are
OK too.

> .) E or C EPROM gone bad, which would cause the CPU to go into Neverland

That's what I was thinking off. There's a lot of -what seems to be- good
activity on the notCS and the notOE signals of the EPROMS. But the data bus
remains very silent (I'm not sure about the activity on the lower part of
the address bus, I'll have to check that).

> .) Reset logic on the motherboard defective, so that the Wave doesn't even
> try to boot. My personal favorite :-)

Yeah, I was thinking about that too, but the machine doesn't respond to
either cold or warm resets.

> .) TAS board or LCD connector broken... since it got no battery, it got no
> sounds, so you won't hear anything even if it boots correctly and just
> doesn't display anything. In that case, the Group A LED should be lit, and
> pressing the GROUP button should toggle between A/B/Both.

None of the Group LEDs are lit when the machine is started. Pressing the
Group button doesn't result in any LED activity.

I'm still thinking that one (or more) of the EPROMS are malfunctioning. I'll
check those when my EPROM reader is ready. In the mean time, any other
suggestions are welcome of course. :)


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