RE: 8250LP - fault, how to fix?

From: Bo Zimmerman (
Date: 2002-02-13 01:25:14

No, the computers RAM.  Thats why it happens regardless of whether the drive
is plugged in or not.  I think you have two seperate problems here.  The
fact that it boots into BASIC at all says good things about the BASIC and

Again, I don't know the SYS to get into the 710 monitor.  The way I did it
(don't laugh.. well, ok, laugh if you want to) is to remove one of the BASIC
ROMs so that the computer would boot into the monitor. :)  I then
progressed, bank by bank, dumping memory values to the screen until I
discovered which bank of memory had a bad bit (it was always set high in my
case).  I then discovered the offending RAM chip and replaced it.

Not saying this is the problem you had, but it might be.  On my machine,
everything was cool one moment, then all of a sudden it would lock up
whenever I tried to issue a disk command.  After fixing the RAM chip,
everything went back to being happy.

- Bo

> -----Original Message-----
> From:
> []On Behalf Of Adrian Vickers
> Sent: Tuesday, February 12, 2002 6:11 PM
> To:
> Subject: RE: 8250LP - fault, how to fix?
> At 23:36 12/02/2002, you wrote:
> >On the 710, I had a 256-80 that did the same darn thing.  The
> problem turned
> >out to be a RAM chip.  You might try going into the monitor
> (don't know the
> >SYS off the top of my head), and dumping the several banks of RAM to look
> >for bits that are suspiciously ON or OFF all the time (the values, by
> >default will alternate).
> Wouldn't that only be true if the drive indicated a fault when
> plugged into
> the machine? It also does it while disconnected from everything.
> OTOH, if you're suggesting scanning the drive's RAM, then I'd be
> curious to
> know where I might find the SYS command, and how it works.
> --
> Cheers, Ade.
> Be where it's at, B-Racing!

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