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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!ihu1g!kma8080
From: kma8080@ihu1g.UUCP (sabalaskey)
Newsgroups: net.micro
Subject: help with drive select on MPI 51-S 5" drives
Message-ID: <688@ihu1g.UUCP>
Date: Wed, 28-Aug-85 10:08:48 EDT
Article-I.D.: ihu1g.688
Posted: Wed Aug 28 10:08:48 1985
Date-Received: Fri, 30-Aug-85 07:53:26 EDT
Distribution: net
Organization: AT&T Bell Laboratories
Lines: 29

I posted this to net.micro.trs-80, which doesnt seem to exist here.

I have a TRS-80 model I (yes, a model I, vintage early 1978). I recently
bought a third disk drive at a flea market which seems to work. It is an
MPI 51-S drive (I think identical to MPI 51-B), which has 40 tracks and
is Singe Sided Double Density. I already had drives 0 and 1 of the same
type.

My problem is that I can get it to work as drive 0, but not any other
drive, 2 or 3. There is a shorting bar for drive select, but I dont have
the schematics to know which bars to set for what. My previous drives
had been set by the company that I bought them from.

One final Note: I have a 4-drive addressed cable, where the select leads
(pins 10, 12, 14, and 32 on the connector) on the cable only go to one
drive each.

Does anyone have:

1) schematics of the MPI 51-S or MPI 51-B drives
2) knowledge to allow me to set the straps appropriately

Any help is greatly appreciated.

Bruce Sabalaskey
AT&T Bell Labs
ihnp4!ihu1h!saba   or   ihnp4!ihu1g!kma8080
(312) 979-6622 before 5PM
(312) 690-2864 after 6PM