15 Dec
2009
15 Dec
'09
7:29 a.m.
How do I identify which board is the video/keyboard interface board? (I
see 4 boards in the card cage)?
How do I identify which chip has failed?
Where do I get replacements?
Thanks!
-Bob
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Mr Ian Primus
Sent: Tuesday, December 15, 2009 8:34 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: trs-80 model II trouble
--- On Tue, 12/15/09, Bob Brown <bbrown at harpercollege.edu> wrote:
When I turn it on, the screen is all inverse
exclamation
points "!".
It says "INSEST!DISKEUTE"
When I close the diskette door, the exclamation points turn
non-inverse
but still cover the screen.
It when boots (in this case I am booting a cpm disk).
The letters seem jumbled up...after booting, I see:
"CQ/MQ!for!tss-81 MOEM II
63k!Version!2/25A
Copyrigit!(c)!1981 Migecoat Associaues"
And it goes to a command prompt.
The rest of the screen is still filled with exclamation
points.
The system does respond as I type things, but letters are
garbled.
Any ideas? Does this sound like some bad
memory? How can I diagnose
this?
It's a bad 2114 RAM chip on the video/keyboard interface board. There
are four 2114's on that board, used for video RAM, and one of them has
failed. I forget if they're in sockets or not...
-Ian