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Re: ][+ troubleshooting
In article <1993Dec7.200153.10907@porthos.cc.bellcore.com>,
Christopher Wood <ccw@ctt.bellcore.com> wrote:
>In article <MORT.93Nov28233540@timeline.apollo.hp.com>, mort@apollo.hp.com (Stephen Moriarty) writes:
>
>|> I have a ][+ that I'm troubleshooting for a friend.
>
>[ ][+; replaced chips on controller, still won't boot disks ]
>
>Sounds like you have a disk speed problem. There's a potentiometer on
>the disk II (you have to open up the case to get to it) that adjusts
>the speed at which the drive runs.
>
>My suggestion would be to hook the misbehaving floppy drives to a
>controller in slot 5 in a working system, and get a program like
>CopyII+ or locksmith to check your drive speed. So you need to have
>at least one working drive on the same system as the faulty ones, so
>you can boot up the software.
The other option, for a system without a working drive, is to remove the
bottom cover as well as the top, flip the drive over (or on the side) and
illuminate it with a fluorescent lamp (and preferably nothing else). Then
(assuming you're in the US) adjust the speed control until the marks labelled
'60' are standing still. In Europe use the marks labelled '50'. That's the
original timing method.
However, if NO disks are booting, that probably means one or more of the
chips on the DRIVE, not the controller card, are bad. Typically it's the
quad buffer chip (74LS121 or something like that) that gets blown. If so,
chances are you're ruining every disk you try to boot in the drive too.
Thus, even when you FIX the drive, those disks will no longer boot!
>
>Chris
>
>--
>Chris Wood Bellcore ccw@ctt.bellcore.com
>
Michael Foegelle
--
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