-----Original Message-----
From: owner-techtoolslist@www.flippers.com [mailto:owner-techtoolslist@www.flippers.com] On Behalf Of John Robertson
Sent: Wednesday, March 26, 2003 6:05 PM
To: techtoolslist@flippers.com
Subject: Re: Issues with the 9010A

Oh, the perils of working when overtired....I looked at this fresh this morning and found the problem was a short between A7 and (inverse)A9! This would not show up as a BUSS fault...

So when you get a floating Address line, look for shorts between it and something else. My logic probe did not identify this as a short as well....only when I had the probe Synched to Address or Data could I identify the problem - so another argument for finding a probe for your 9010A!

John :-#)#

Updated slightly as per some questions raised in email...

I was tinkering around with a sick Bally MPU board today (a rewired -17 monster for Grand Products 301), and was trying to figure out why the 6810 was not being selected...So I set the probe to SYNC to DATA (or ADDRESS), and set a WRITE @ 0000 = 55 (LOOPING), and then tried checking with the 9010A's probe for results. Curiously enough, the Synched probe showed nothing at all for A7 - Tri-State as far as it was concerned. I though maybe the 6800 pod was defective and pulled out another one, same result. A regular logic probe shows everything active. Need to dig out the scope next I guess...

The 6810 RAM should have been available from 0000h to 007Fh, but it was invisible. The 6810 is good, as is the socket and wiring...curious... shall dig around more tomorrow when had more sleep and let you folks know the results.

A FAQ on the 9010A might be in order at some point...

Suggestions?

John :-#)#

How to subscribe or unsubscribe from TTL

To do either you send email to "MajorDomo@flippers.com" and in the body you state either "Subscribe techtoolslist" or "Unsubscribe techtoolslist", note that the Subject is "" (Blank)...

FTP site is: ftp://ftp.flippers.com/TTL/