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AST RESEARCH, INC.         TECHNICAL BULLETIN # 1213                6-14-95

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DESKTOP SYSTEMS AND LITE-ON KEYBOARDS


PROBLEM

After booting to DOS, AST desktop systems may show several characters on 
the screen following the C:> prompt.  These characters appear to have been 
typed via the keyboard.  The characters can be deleted by pressing the 
<Backspace> key several times.

The user may also be unable to log into a Novell Netware operating system 
because the keyboard buffer is full of hidden characters.


CAUSE

Incompatibility between the AST keyboard controller and the Lite-On 
keyboard BIOS.


SYSTEMS AFFECTED

Any AST systems using a Lite-On keyboard (AST part number 202851-001).


SOLUTION

The keyboard controller as well as the Lite-On keyboard BIOS have been 
upgraded with a revision of the system board or keyboard. 

The solution is to take the system to an AST Authorized Service Center for a 
system board replacement.  See part numbers and revision levels below.


CAUTION

This modification should be performed ONLY by a qualified service technician.  
It is strongly recommended that this change be completed by an AST Authorized 
Service Center.  In no case will AST Research, Inc. be liable for damage to 
the system and its components, or loss of data caused by improper modification.


PREREQUISITES

A full backup of all data on the hard drive in the computer is strongly 
suggested.


TIME REQUIRED

30 minutes.


STATUS VERIFICATION

The revision level of the AST system board can be identified by observing 
the revision letter at the end of the nine-digit part number located on the 
solder side of the system board.


PARTS REQUIRED
AST PART NUMBER          DESCRIPTION                         REVISION

202604-XXX              PCBA MBD PRM GX                      X16 or higher
202612-XXX              PCBA MBD BRAVO MS 4-00               X16 or higher
202620-XXX              PCBA MBD CHANNEL 1 SCSI SMT          X18 or higher
202637-XXX              PCBA MBD PRM MX                      D
202652-XXX              PCBA MBD P90                         X05 or higher
202653-XXX              PCBA MBD P60                         X17 or higher
202654-XXX              PCBA MBD ASYNCH                      X15 or higher
202670-XXX              PCBA MBD DX-00                       X05 or higher
202671-XXX              PCBA MBD P-0                         X14 or higher
202694-XXX              PCBA MBD BMS-L 00                    X25 or higher
202695-XXX              PCBA MBD CMT 4-00                    S
202705-XXX              PCBA MBD BMS 4-00                    X10 or higher


TOOLS REQUIRED

Standard computer tools.


INSTALLATION PROCEDURE

Refer to the system Hardware Maintenance Manual.

Removal and replacement of system "Field Replaceable Units" (FRUs) should 
only be performed according to the installation procedures approved and 
prescribed by AST Research, Inc.  

Remove the system board according to procedures approved and prescribed by 
AST Research, Inc.


CHECK-OUT PROCEDURE

To verify proper operation of the system upon completion of this change, 
follow the setup and test procedures described in the AST User's Manual.


NOTE

Warranty reimbursement for this change requires prior AST Research, Inc. 
approval. 

The warranty on this system will become VOID if this change is completed 
by ANYONE other than an AST Authorized Service Center.