Ruud's diagnostic ROM fitted to the 16KB-64KB version of IBM 5150 motherboard
You are here because:
- you have the 16KB-64KB version of IBM 5150 motherboard; and
- you got the Supersoft/Landmark diagnostic ROM running on it; and
- you are aware that RAM checking on a 16KB-64KB motherboard by the Supersoft/Landmark diagnostic ROM is unreliable; and
- you now wish to use Ruud's diagnostic ROM to see if RAM bank 0 on the 16KB-64KB motherboard is good.
Ruud's diagnostic ROM is based on the Supersoft/Landmark diagnostic ROM, but unlike that ROM, Ruud's diagnostic ROM will stop RAM testing at the first RAM error.
Ruud's diagnostic ROM requires an MDA or CGA video card.
Note that for the 16KB-64KB version of IBM 5150 motherboard, Ruud's diagnostic ROM does not require that motherboard's RAM related switches on SW1 and SW2 be set correctly.
The RAM chip for parity is not tested, but for what we are doing here, it does not need to be. That is because if bank 0 has one faulty RAM chip, and it is the chip for parity, the POST in the IBM BIOS ROM will start and display something on-screen.
RAM refresh circuitry is not tested, but for what we are doing here, it does not need to be. Why? If faulty RAM refresh circuitry is the only problem, the POST in the IBM BIOS ROM will start and display something on-screen. More information about that is at here.
What is expected to be seen
The partial screen shot at here shows what is expected to appear when the 16KB-64KB motherboard's RAM subsystem (four banks of RAM chips, plus supporting circuitry except for RAM refresh) is functional.
The partial screen shot at here shows what is expected to appear when only bank 0 has RAM chips in it.
The partial screen shot at here shows what is expected to appear when:
- one (or more) of the RAM chips in bank 0 is faulty in a way that affects all of its addresses; or
- one (or more) of the RAM chips in bank 0 is faulty in a way that only affects an address (or multiple addresses) somewhere in the first 2K of its addresses; or
- lack of +12V reaching the RAM chips (all are 4116 type); or
- lack of -5V reaching the RAM chips (all are 4116 type); or
- incorrect type of RAM chip/s in bank 0; or
- a fault in the RAM subsystem, other than faulty RAM chips, a fault that affects at least the first 2K of RAM.
Download for W27E257 EEPROM (i.e. 32 KB sized)
Click here for a ROM image suitable for a W27E257 EEPROM.
Just like for the Supersoft/Landmark diagnostic ROM, a suitable adapter will be required to use a W27E257 on a 5150 motherboard - see option #4 at here.
Download for 27256 EPROM (i.e. 32 KB sized)
Click here for a ROM image suitable for a 27256 EPROM.
Just like for the Supersoft/Landmark diagnostic ROM, a suitable adapter will be required to use a 27256 on a 5150 motherboard - see option #3 at here.
Download for 27128 EPROM (i.e. 16 KB sized)
Click here for a ROM image suitable for a 27128 EPROM.
Just like for the Supersoft/Landmark diagnostic ROM, a suitable adapter will be required to use a 27128 on a 5150 motherboard - see option #3 at here.
Download for 2764 EPROM (i.e. 8 KB sized)
Click here for a ROM image suitable for a 2764 EPROM.
Just like for the Supersoft/Landmark diagnostic ROM, a suitable adapter will be required to use a 2764 on a 5150 motherboard - see option #3 at here.
Download for 2564 EPROM (i.e. 8 KB sized)
Click here for a ROM image suitable for a 2564 EPROM - see option #2 at here.
No adapter required for a 2564 (note: 2564 not 2764).
Download for MCM68766 EPROM (i.e. 8 KB sized)
Click here for a ROM image suitable for a MCM68766 EPROM - see option #1 at here.
No adapter required.