IBM 6150 Hardware Maintenance Manual

TNL SN20-9843 (03-27-87) to 75X0152 or 75X0166Power-On Self-Test2-6 Service ManualThe resident Power-On Self-Test (POST) programs are in Read-OnlyMemory (ROM) modules on the processor board. These programs runwhen the system unit is first powered on. When the resident POSTprograms complete, additional POST programs load from the fixed disk orfrom the diagnostic diskettes.Numbers display on the two-digit display to track the progress of the POSTprograms. Some tests may run so quickly that the numbers may not bevisible.Note: The following chart is for "steady" numbers only. Flashing (aboutone second) numbers are for software failures. See "Two-Digit DisplayCodes During Diagnostic Programs" on page 2-18 for flashing numbersduring the diagnostic checkouts.Number Test description88 Displays for one second to provide a lamp test. If "88" isdisplayed steady, the 32-bit processor has stopped.OO,Oc If installed, this test resets the IBM Monochrome Display andPrinter Adapter.01, lc Tests the ROM modules on the processor board.02 Tests for correct communication between the 32-bit processorand the system board.03,3c Tests the memory controller on the processor board and thesystem memory boards in slots C and D.04,4c Tests the processor board.05,5c Tests the processor board.07,7c Tests the I/O channel controller on the system board.