John, you mention a logic comparator, what model do you use?
David
-----Original Message-----
From: owner-vectorlist@synthcom.com
[mailto:owner-vectorlist@synthcom.com]On Behalf Of John Robertson
Sent: Friday, August 18, 2000 9:50 AM
To: vectorlist@synthcom.com; techtoolslist@flippers.com
Subject: VECTOR: TECH: Omega Race, Kruz-Kash, and the Fluke 9010A
I just thought I'd bore you folks with some experiences I had fixing up an
Omega Race PCB...
Pulled from stock, one very nice looking OR boardset-no corrosion at all
battery was removed years ago, looked like an easy sale so pulled out the
old KK test fixture and wired up my Hoie XY monitor. Dead. Disabled
Watchdog, and pulled out Fluke and plugged into Z80 socket, hmmm, can't
read any memory at all, yet Data Bus test is OK. Pulled 5101 and plugged
into the 5101 test fixture (a Stern pinball MPU with zip sockets)-dead,
ties data bus up. New 5101, still no reliable memory read, pulled out logic
comparator, and found bad 7432 (-memw), now could read RAM. Lots of ram
failures (turned out to be 5 bad 2114s), now couldn't read 2732s reliably,
dig more with comparator, bad 74ls08, now can read some Eproms. Pulled 0h
ROM, now could read all eproms. Hmm, check 0h Rom on programmer...Ok? Burn
a new one, now all Rom checks out (anyone like Fluke sigs for Erpoms?).
Repair Watchdog. Hook back up to XY, good picture, but Y pot does nothing,
turns out the 10K resistor is open. Now it works....total time about five
hours....sigh...never should start these old buggers some days.
John :-#)#
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
http://www.flippers.com
"Old pinballers never die, they just flip out."
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Received on Sun Sep 17 16:38:48 2000
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