Parent 

Supersoft/Landmark Diagnostic ROM
suitable for most clones of the IBM AT


This is not a clone specific version of the diagnostic.  It is exactly the same diagnostic targeted for the IBM PC family.  From the user manual, "IBM PC, XT, AT-286, AT-386, AT-486, or 100% compatible".

The "100% compatible" is Supersoft 'giving themselvs an out'.  Why?  Because there is no such thing as a 100% compatible clone.  In some clones, one or more tests will fail, even if the clone is fully functional.

This is the AT variation of the diagnostic, intended for the IBM 5162, IBM 5170 (IBM AT), and clones of those.

You remove the BIOS ROM from the motherboard, and in its place, fit the Supersoft/Landmark Diagnostic ROM.  In some cases, the BIOS is one ROM, and in other cases, it is two ROM's.

An example screen output is shown at here.

Before reading further, make sure that you have read the information in the parent web page at here.


Important Notes:

• There is a 20 second delay before anything is seen on the display.  Sometimes more.  Be patient.  See note 2.     <--- Do not fall for this trap 
• At power-on time, this AT version of the Supersoft/Landmark ROM's is known to erroneously beep the speaker with a pattern that the user's manual (page 40/41) indicates "Cannot initialize monitor".
• Some video cards will not work with this AT version of the Supersoft/Landmark ROM's.

- My functional IBM MDA card does not work (no beeps, no display).  My second functional IBM MDA card does the same.
- My IBM CGA card works.
- My IBM EGA card (only 64 KB RAM fitted) will display, but poorly.  Supersoft appears to think that I have CGA.

- My clone MDA card (unbranded) works.
- My clone CGA card (unbranded) works.
- My clone EGA card (an AST-3G) initially displays this, but then displays normally once the EGA memory test has finished.

- None of my VGA cards work.  More information here.
• Per the user manual, the MEMORY AT 000000 test will check conventional memory up to 640 KB, then test extended memory (address 1 MB onwards).
The memory size figures in CMOS SETUP are ignored.
At some point, the test will encounter memory that does not exist, and as a consequence, you will see errors.
For example, if the only RAM is the 512 KB on the motherboard, then expect errors after address 80000.
• On a 6 MHz AT, the PROTECTED MODE CPU  test takes 25 seconds to complete.  Be patient.
• On my fully functional IBM AT motherboards, the  PROTECTED MODE CPU  test does something odd.  Three things happen:
    1. On the speaker, I hear the error pattern for "Cannot initialize monitor".
    2. If I am using an IBM CGA video card, I see what appears to be 'CGA snow'.
    3. "1 FAILED" is written to the top line.  (photo)
The PROTECTED MODE CPU test is then indicated as "PASSED", then testing continues.


Minor Notes:

• The Supersoft/Landmark ROM's even generate a display if there is no RAM on the motherboard.  More information here.
• No battery required.
• There is nothing in the manual that indicates that the Supersoft/Landmark ROM's output POST codes.
• With no keyboard connected, the  U126 KEYBOARD CONTROLLER and  KEYBOARD SCAN LINES  tests pass.
• Operation of the A20 gate is not tested.


Images (content) to be programmed into EPROM

To create a Supersoft/Landmark ROM, you program/write ('burn') an image into a suitable EPROM.  An EPROM programmer is required to do that.  That EPROM replaces the motherboard's BIOS ROM.

There are some people/companies shown at here who can supply EPROM's, programmed/written ('burned') to your requirement.

Find out what EPROM type your AT clone motherboard uses, then choose the appropriate image below.

Type of EPROM/EPROM's Size Image download   Comment
One 27256 (27C256) EPROM 1  x  32 KB Download  See note 1 below.
Two 27256 (27C256) EPROM 2  x  32 KB Download  One odd (high) EPROM and one even (low) EPROM.   See note 1 below.
One 27512 (27C512) EPROM 1  x  64 KB Download  32 KB image that has been doubled.




Note 1 Per here, a Winbond W27E257 can be used in place of a 27256 or 27C256.
   
   
Note 2 This is a known bug in the AT variation of the diagnostic.  What is happening is that the diagnostic is in error, declaring a 'Cannot initialize monitor' error, and taking about 20 seconds to send {six high/low beep sequences followed by one short beep} to the speaker.  For that reason, make sure that you have a speaker connected to the motherboard.

But my Forex chipset based motherboard takes about 45 seconds before video appears.  That is because, the 'Cannot initialize monitor' error is being followed by a second error, all up, taking about 45 seconds.