RE: Cinematronics CPU board problem

Could be bad scratchpad RAM. Try replacing the 2102A’s @L-14, M-14 and N-14.

Dave

From: owner-vectorlist@vectorlist.org [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Matt Rossiter
Sent: Monday, January 19, 2009 11:52 AM
To: Vectorlist
Subject: Re: VECTOR: Cinematronics CPU board problem
Importance: Low

Man, I feel your pain there. I have a couple of boards like that too.

Sometimes you need to reverse the clock position to get alternate signatures as listed in the manual.
Double-check the power-up circuit on Page 5 of 7
Make sure the JMI jumper is set correctly, which I'm sure it is.

You might have to scrap the signature analysis and start from the RESET line with an oscilloscope and work back that way.

Other than that - hopefully some of the experts on this list can advise you because I could use a little help as well. :)

Matt

On Sun, 18 Jan 2009 22:37:38 -0500, "William Boucher" <boucher@mnsi.net> wrote:

Has anyone ever been doing Cine CPU troubleshooting using an exorciser setup and found 100% of the signatures to be correct but the board still won't run? I'm having this problem with a Rip Off CCPU. It is not a mod'ed board (meaning it uses 2716 eprom's). I've tested or replaced about 30 chips including the eproms, a few bipolar d_roms, some 74LS163 counters that were messed up, a few gates, all the 74LS377's, the 74LS181's, the ram chips, all of the original chip sockets, and so on. Like I said, all the sigs are perfect. I tried the "load loop timer" test, the "spac" test, the "no-op" test, and the standard test. I've done them all 3x or more. The old original docs are loaded with numerical errors but I have sorted them all out already. The PCB is very clean, no open traces that I can find, no missing pads, no broken resistors or caps, etc. It is visually perfect. All the clock signals are perfect as well.

I had a stack of about 10 old CCPU's and I finally decided to repair them all. I whipped through the batch and fixed 6 of them within a couple of days. I'm now down to just 3 left. I probably should move on to the last 2 boards and come back to this one last, but I don't want to let it beat me. I'll keep at it even if I have to replace every last chip on the whole board one at a time if that's what it takes. At this point, I'm simply out of ideas.

One of my other boards that doesn't work also has all good signatures as well. I can only hope that it doesn't turn out to be the same nightmare all over again. I don't really understand how all of the signatures can be correct and the roms all verified and the ram replaced with known-good chips and the thing still won't run.

Any thoughts or suggestions?

William Boucher

http://www.biltronix.com/arcade_01.html

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Received on Mon Jan 19 16:46:00 2009