IBM 5170 Motherboard - ROM information
BIOS ROM's
U72
U115
Related
BIOS ROM's
Type 1 motherboard
On early 5170 motherboards of type 1, there are four 16 KB sized BIOS ROM chips (of type 27128), in sockets U17/U27/U37/U47. (photo)
Accordlingly, shunt block U131 is set to the '27128' position.
Later, two 32 KB sized BIOS ROM chips (of type 27256) were supplied instead, one in socket U27 and the other in socket U47.
Accordlingly, shunt block U131 is set to the '27256' position.
Type 1 motherboards were supplied with the 01/10/84 revision of BIOS. Additional information about that is at here.
6 MHz motherboard. Required are ROM's of a maximum access time of 260 ns. (source)
Type 2 motherboard
On a type 2 motherboard, there are two 32 KB sized BIOS ROM chips (of type 27256), one in socket U27 and the other in socket U47.
These motherboards were supplied with the 06/10/85 revision of BIOS. Additional information about that is at here.
6 MHz motherboard. Required are ROM's of a maximum access time of 260 ns. (source)
Type 3 motherboard
On a type 3 motherboard, there are two 32 KB sized BIOS ROM chips (of type 27256), one in socket U27 and the other in socket U47.
These motherboards were supplied with the 11/15/85 revision of BIOS. Additional information about that is at here.
8 MHz motherboard. Required are ROM's of a maximum access time of 190 ns. (source)
Chip U72
IBM's circuit diagram for the IBM 5170 motherboard of type 1 has U72 indicated as being type 28S42, which is a 512-byte PROM of a particular pinout.
In a type 1 5170 motherboard photo at here, U72 is stamped with the IBM part number of 6323541.
On my type 3 motherboard, the fitted PROM is a Signetics N82S147AN (a 512-byte PROM), and has the IBM part number of 55X8041 printed on it.
Other IBM part numbers for this part may exist.
Content of the chip: 55x8041.82s147an.u72.bin (source: here) (originates from the MAME project)
Chip U115
On all three types of IBM 5170 motherboard, chip U115 is a 32-byte PROM, of a particular pinout.
The PROM type fitted will be either: 74S288, 82S123, or 63S081.
On my type 3 motherboard, the PROM is a Signetics N82S123AN, and has the IBM part number of 1501814 printed on it. (Other IBM part numbers for this part may exist.)
The content in the chip is the same as that for chip U72 in the IBM 5162.
Content of the chip: 1501814.82s123an.u115.bin (source: here) (originates from the MAME project)
Related
On the IBM 5170 motherboard are also PAL chips. See here.