Parent

Supersoft/Landmark Diagnostic ROM for 16KB-64KB version of IBM 5150 motherboard



WARNING: If your 16KB-64KB motherboard has a RAM related problem, the Supersoft/Landmark Diagnostic ROM is known to display incorrect and misleading information.
It is though the Supersoft/Landmark Diagnostic ROM is not intended for the 16KB-64KB version of IBM 5150 motherboard.
Click here for a list of known bugs.

For the 16KB-64KB motherboard, if you want to see if RAM bank 0 is good, then I suggest that you use Ruud's diagnostic ROM.



Four RAM banks of 16 KB each.

Bank 0: 16 KB sized,  addressed 0000 to 3FFF hex  (  0 KB to 16 KB)   (soldered to motherboard)
Bank 1: 16 KB sized,  addressed 4000 to 7FFF hex  (16 KB to 32 KB)   (socketed)
Bank 2: 16 KB sized,  addressed 8000 to BFFF hex  (32 KB to 48 KB)   (socketed)
Bank 3: 16 KB sized,  addressed C000 to FFFF hex  (48 KB to 64 KB)   (socketed)


On an IBM 5150 motherboard, socket U33 is where the Supersoft/Landmark ROM needs to be placed.

To use a 27xxx series EPROM (e.g. 2764/27128/27256/27512) in socket U33, you will require a suitable adapter (adapter details).

U33 image for a 2764 EPROM (or 27C64) in a MK36000/2764 adapter ( or in 2364/2764 adapter, such as the one at here )
U33 image for a 27128 EPROM (or 27C128) in a MK36000/27128 adapter ( or in 2364/27128 adapter, such as the one at here )
U33 image for a 27256 EPROM (or 27C256) in a MK36000/27256 adapter ( or in 2364/27256 adapter, such as the one at here )
U33 image for a 27512 EPROM (or 27C512) in a MK36000/27512 adapter ( or in 2364/27512 adapter, such as the one at here )



Important Notes:

Read the earlier warning about RAM related bugs.
Some video cards will not work with this PC (and XT) version of the Supersoft/Landmark ROM.

- My IBM MDA card works.
- My IBM CGA card works.
- My IBM EGA card will display, but poorly.

- My unbranded clone MDA card works.
- My unbranded clone CGA card works.

- None of my VGA cards work.  More information here.

If a RAM error at address 05040 is reported, note that the "05040" bit is incorrect.  Do not believe the "05040" - the diagnostics have displayed the wrong address.
The SYSTEM MEMORY TO 10000  test will fail if 64 KB (10000 hex = 64K) of RAM is not fitted.
So, that is 64 KB on the motherboard (all four RAM banks populated).
RAM related switches on the motherboard are ignored (switches SW1:3 and SW1:4, and SW2).
The KEYBOARD CONTROLLER  test will fail if no PC-class keyboard is connected to the 5150 motherboard.
The FLOPPY CONTROLLER  test requires that a floppy controller card is fitted to the 5150 motherboard.  For this test, the card does not need any drives connected to it.
The FLOPPY READ  test takes about 1.5 minutes to fail.  Be patient.
The NONMASKABLE INTERRUPT  test is known to fail if either:
   - Math coprocessor (8087 chip) is absent and you have switch 2 on SW1 in the wrong position for that (off).
   - Math coprocessor (8087 chip) is present and is faulty.
The U28 ROM  test is expected to fail, because there is nothing in the U28 socket.


Minor Notes:

It is observed that when a test fails, the Supersoft/Landmark ROM switches the motherboard relay on/off three times.  (The clicks are very audible.)
The settings of the switches within SW1 on the 5150 motherboard are ignored, except for switch 2.
The settings of the switches within SW2 on the 5150 motherboard are ignored.
Switches 3 and 4 within SW1 on the IBM 5150 motherboard do not enable/disable RAM banks.  The 4 motherboard banks are always enabled.  That is why in the IBM 5150, all motherboard RAM banks must be populated before RAM is added via expansion card/s.
Ignore the box labelled, "XT SW1".  That is for when the ROM is used in an IBM 5160 (IBM XT).
The term 'KEYBOARD CONTROLLER' is misleading.  Unlike the IBM 5170, the IBM 5150 does not have a keyboard controller chip.  Discrete components are used instead.
There is nothing in the manual that indicates that codes are sent to port 80h.
An example output is shown at here.