PS/2 Model 30, 8086-8MHz CPU BIOS Versions:

68X1627/68X1687: 09/02/1986 - Revision '0'
61X8937/61X8938: 12/12/1986 - Revision '1'
61X8939/61X8940: 02/05/1987 - Revision '2'
    - Revision '3' not released -
33F4498/33F4499: 01/31/1989 - Revision '4'