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AST RESEARCH, INC.          TECHNICAL BULLETIN # 1179                4-5-95

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INSTALLING A HARD DRIVE INTO THE MANHATTAN P-SERIES DRIVE TRAY


PROBLEM

The Manhattan P-series and the Manhattan XP expansion cabinet use a SCSI 
backplane which requires that hard drives be mounted in a special drive tray 
(AST part number 500922-0030).  

This Technical Bulletin documents the procedure and special considerations 
for installing a third-party SCSI drive into the drive tray.


CAUSE

The jumper settings and cable connections required for drive tray installation 
are not intuitive.  The AST SCSI Backplane Option Guide, AST part number 
003096-001, documents only part of this procedure.


SYSTEMS AFFECTED
AST PART NUMBER DESCRIPTION

501502-XXX     AST Manhattan P-Series
501516-001     AST Manhattan XP Expansion cabinet


SOLUTION

The following are the requirements to install a hard drive into the drive tray:

1. The drive must not have termination enabled.

2. The drive I.D. cable from the drive tray must be connected properly to the 
drive I.D. selection jumpers on the drive.

To accomplish requirement (1), follow the instructions provided with the 
drive for disabling termination on the drive.  Usually this will involve 
either removing a set of resistor packs from the drive, or removing a 
"termination enable" jumper (typically labeled "TE").

In order to accomplish requirement (2), the jumpers on the drive that control 
the SCSI ID selection must be identified.  Again, consult the instructions 
provided with the drive.  

Typically, the jumper pairs used to control the SCSI ID selection will be 
labeled "A0", "A1", and "A2".  The drive ID cable is the six-conductor cable, 
which runs from the backplane connector to the drive.  
It should be connected to the three jumper pairs that control the SCSI ID 
selection, with the end of the connector containing the red wire connected to 
the jumper corresponding to "A0."  

If the SCSI ID jumpers are not labeled "A0", "A1", and "A2", they can 
usually be identified by a chart in the drive documentation, which details all 
possible SCSI ID assignments, and the corresponding jumper settings.  
The jumper configuration for ID "1" will show only the "A0" jumper pair 
connected, while the configuration for ID "2" will show the "A1" pair 
connected, and the configuration for ID "4" will show only the "A2" pair 
connected.   
For example, the Seagate ST-15230N drive labels the jumpers "ID-1", "ID-
2", and "ID-4",  which correspond to "A0", "A1", and "A2" -- On this drive, 
the drive ID cable should be installed on the "ID-1", "ID-2", and "ID-4" 
jumper pairs, with the red wire on the "ID-1" end.

If there are multiple jumper sets which can be used to select the SCSI ID, all 
jumpers should be removed from any ID selection jumpers that are not 
connected to the drive ID cable.

The remainder of the installation (power cable, 50-pin SCSI cable, and 
mounting screws) follows exactly as documented in the AST SCSI Backplane 
Option Guide (part number 003096-001).

A newer revision of the AST SCSI Backplane Supplement (AST part number 
003281-001 A), due to be released in May, 1995, will contain more detail and 
illustrations about this process.