THANKS! Write @ 0 = FF Write @ 1 = 00 Read @ 0 return F0 I need to update my manual RAM checker too. JB

-----Original Message----- From: James S. Bright [mailto:james@quarterarcade.com] Sent: Saturday, April 19, 2003 7:34 PM To: 'techtoolslist@flippers.com' Subject: RE: 9010A, Not sure what this means...

Thanks. This is very helpful...

JB

--James Bright www.QuarterArcade.com Restored Arcade Games for your Home

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-----Original Message----- From: Mark Shostak (DOS) [mailto:shostak@augustmail.com] Sent: Saturday, April 19, 2003 7:27 PM To: James S. Bright; techtoolslist@flippers.com Subject: Re: 9010A, Not sure what this means...

If I read your question correctly,

It's complaining about an address decoding error, specifically with bit A0. So, it found that when it wrote a value to an address, then changed bit A0, the value it wrote to the previous address appeared at this other address.

Try your manual test again: write 55 to 0 (and read back) write AA to 1 (and read back) read 0 again and see if it's 55 or AA also try it the other way (if writes to loc 0 appear at loc 1)

That's the basic idea. Bit 0 is about the easiest one you could have hoped for to learn on. Hope that helps.

-Mark

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Working on a Centipede (6502 based).

RAM test (Short or Long) on RAM that I think is good, I get

"RAM DCD

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ERR @ 0000 BIT 0". I'm not sure what this means. I've tested the buffer chips (data and address) and they appear to be okay. When I run custom tests (reading and writing AA/55), the RAM seems okay. Can anyone elaborate on this error message? The manual didn't really help out. I'm not exactly sure what to do next with this board.

(This board doesn't play blind, and nothing appears on monitor.)

TIA.

JB

--James Bright www.QuarterArcade.com Restored Arcade Games for your Home