Red Alert help needed (6502 CPU question too)

From: Franklin Bowen <Franklin_at_Bowen.net>
Date: Sun May 02 2004 - 09:58:37 EDT

I posted something similar on RGVAC and got no response so I though I would
try it here.

Does anyone have a different manual than the one on-line (my board is about
20% different, mostly parts not populated, than this manual)?
If so, can I borrow, buy, or get a scan of it?
If not, does anyone have better scans of the Main Logic pages or schematics
I can borrow/buy?

The voltages on the board are perfect. The thing I can't figure out is why
the CPU address lines are all low! I have placed my logic probe on them at
power up and I never notice the high light activate or the tone
change. But maybe it happens too quickly for it to be noticeable? I
swapped the CPU with another (neither verified good) and got the same
results. Stable picture of garbage with no noticeable activity.

So here is what is happening at the CPU:
/RESET starts low, then stays high
Clock in (pin 37) is 733.2 KHz. Supposed to be 1MHz according to MAME.
Clock outs both 733.2 KHz.
A15-A0 are all stuck low.
D7-D0 all pulse.
R/_W is high
SYNC is low
/NMI is high
/IRQ is low (I pulled the driving chip and tied the signal high. No change)
RDY is low

What would make the address lines all "stick" low? Anyone have a Red Alert
board running at 733.2 KHz?

Thanks!

--
Franklin Bowen (Franklin_at_Bowen.net)http://fmbbowen.com:39353 
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Received on Sun May 2 10:07:41 2004

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