AST RESEARCH TECHNICAL BULLETIN TB-0002                   4-16-84

      POWER-ON SELF TEST ERROR ON XT AND PORTABLE COMPUTERS


When  the IBM-XT or portable computer is powered-on,  the  system 
BIOS initializes a Power-On Self Test (POST).  In the upper left-
hand corner of the screen,  the progress of the POST is displayed 
in the format:

                            XXX KB OK

The  number (XXX) should continue to increase until it equals the 
amount of memory installed in the system.   Normally,  this  test 
takes  23 to 90 seconds to complete,  depending on the amount  of 
memory  installed.   Upon completion,  the system will attempt to 
boot the diskette in drive A.

However,  if switch 1 of the switch system board switch block  is 
"ON",  the  POST  will re-initialize and start over.   This  will 
continue in an endless loop.

This  problem can be resolved by removing power from the  system, 
positioning  switch 1 in the "OFF" position and then  re-applying 
power to the system.

The IBM Guide to Operations refers to this switch only as "Normal 
operation; always off".