[Test-Equipment] Trak Systems 8820 - Need assistance

[Mark Richards]

I'm totally unfamiliar with the unit itself, but suggest that (if you
haven't tried this already) you make certain that more than one input is
being held closed (a stuck keypad or short somewhere).  That could fowl up
the works in any rudimentary input scheme.

If the keypad is on a different CPU than the display, you might also check
to see if you have clock, dc voltage is at correct value, etc.

Sounds like a fun toy.

/mark richards 

-----Original Message-----
From: test-equipment-bounces at mailman.qth.net
[mailto:test-equipment-bounces at mailman.qth.net] On Behalf Of Bruce Lane
Sent: Tuesday, March 14, 2006 21:55
To: test-equipment at mailman.qth.net
Subject: [Test-Equipment] Trak Systems 8820 - Need assistance

Fellow techies,

	I've become the proud owner of a slightly sick Trak Systems 8820 GPS
clock. It has an unusual problem in that the ToY display runs just fine, but
the microprocessor that controls the unit's options and LCD display panel
does not seem to be initializing. I determined this after speaking with
folks at Trak, and eliminating the possibility that the display was the
problem.

	Some random probing of the suspect CPU's address/data lines with an
O-scope reveals practically no activity. I'm wondering if something is
holding the reset line active...? Or perhaps I've got one or more failed bus
transceivers? Heck, I've even entertained the possibility that the CPU chip
itself (an Intel 80C188) is bad.

	If there are any other owners of these units that may have run into
similar problems, I'd appreciate hearing from you.

	Thanks much.


-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies --
http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If
Salvador Dali had owned a computer, would it have been equipped with surreal
ports?"

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