214 lines
9.4 KiB
Plaintext
214 lines
9.4 KiB
Plaintext
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AST RESEARCH TECHNICAL BULLETIN TB-0055 9-21-84
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FAULT ISOLATION OF THE IBM PC-1
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USING THE POWER ON SELF TEST (POST) DIAGNOSTICS
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Each time the IBM PC-1 (64K motherboard) is powered on, the ROM
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BIOS initiates a built-in set of diagnostic tests to determine
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the functionality of the hardware.
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These tests are also performed (with the exception of the RAM
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test) each time a "warm boot" is initiated (Ctrl-Alt-Del).
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Failures to the diagnostic tests can be caused by component
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failures on the system motherboard, errors in switch settings, or
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a defective expansion board. These failures are indicated by a
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sequence of beeps, error codes on the CRT display or both.
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The attached tables present the tests in the order in which they
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are performed. Thus, if an error is detected, fault isolation
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can be accomplished as the tests above the failure have been
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completed successfully.
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Table 1 is applicable to an IBM PC-1, which is NOT fitted with
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either a "bootable" harddisk or an IBM Expansion Chassis.
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Table 2 is applicable to an IBM PC-1, which is fitted with either
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a "bootable" harddisk or an IBM Expansion Chassis.
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TABLE 1
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POST ERRORS FOR IBM PC-1 WITHOUT EITHER AN
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IBM EXPANSION CHASSIS OR A BOOTABLE HARDDISK
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SYMPTOM CAUSE
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1. System does not respond The power supply has shut
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at all when turned on. down,
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OR:
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The 8088 has HALTed due to:
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- Internal 8088 problem.
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- BIOS ROM checksum error.
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- 8253 timer problem.
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- 8237 DMA controller error.
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- Error in last 16K of RAM.
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Note: Try turning off power
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supply, waiting 5 seconds,
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then turning it on.
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2. System beeps: The 8088 has HALTed due to:
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1 long beep (3 seconds), - 8259 interrupt controller
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1 short beep (1 second), error.
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then stops. - 8253 timer counting too
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fast or slow.
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3. System beeps: Checksum error in a BASIC ROM.
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1 long beep (3 seconds),
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1 short beep (1 second),
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but continues the power-
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up sequence.
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4. System beeps: Error in video RAM or error in
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1 long beep (3 seconds), 6845 video circuitry.
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2 short beeps (1 second
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each), continues power-
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up sequence.
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5. System beeps: The display card is probably not
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1 long beep (3 seconds), installed.
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2 short beeps (1 second),
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1 long beep (3 seconds),
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2 short beeps (1 second
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each).
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6. 'XXYY 201' appears at the RAM error. XX = the high order
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top of the display, where byte of the failing segment,
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XXYY = four hexadecimal e.g.; XX = 20 would indicate
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digits. that the error occurred between
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segment 2000 and segment 2400.
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(Memory is tested in 16K
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blocks, each 64K increments the
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segment by 1000. YY = the
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failing bit pattern, which can
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isolate the specific RAM.)
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7. 'XX 301' appears at the Keyboard error. Usually a stuck
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top of the display, where key, where XX = scan code of
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XX = two hexadecimal digits. the stuck key.
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8. '131' appears on display. Cassette port error.
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9. '601' appears on display. Disk drive A, or disk adapter
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error.
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10. 'PARITY CHECK 1' appears. A RAM parity error has occurred
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on the system motherboard. The
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INT 2 routine in the BIOS gains
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control and HALTs the 8088 when
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a memory parity error occurs.
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Parity checking had been
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DISABLED prior to this point in
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the test sequence, and is en-
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abled here just before reading
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the boot record from the disk.
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11. 'PARITY CHECK 2' appears A RAM parity error has occurred
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on the display. on an add-on memory board. This
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message comes from the BIOS
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ROM's INT 2 routine, which then
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HALTs the 8088.
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12. System beeps: This is normal system reponse
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1 short beep (1 second). just before the system boots
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from the disk. The system has
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successfully passed the diag-
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nostics.
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TABLE 2
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POST ERRORS FOR IBM PC-1 WITH AN IBM
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EXPANSION CHASSIS OR A BOOTABLE HARDDISK
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SYMPTOM CAUSE
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1. System does not respond The power supply has shut down,
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at all when turned on. OR:
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The 8088 has HALTed due to:
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- Internal 8088 problem.
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- BIOS ROM checksum error.
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- 8253 timer problem.
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- 8237 DMA controller error.
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- Error in last 16K of RAM.
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Note: Try turning off power
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supply, waiting 5 sec-
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onds then turning it on.
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2. System beeps: The 8088 has HALTed due to:
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1 long beep (3 seconds), - 8259 interrupt controller
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1 short beep (1 second), error.
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then stops. - 8253 timer counting too
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fast or slow.
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3. System beeps: Error in video RAM or error in
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1 long beep (3 seconds), 6845 video circuitry.
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2 short beeps (1 second
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each), continues power-
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up sequence.
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4. '1801' appears at the top Error in expansion unit inter-
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of display. (If IBM Expan- face.
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sion Unit is installed).
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5. 'XXYY 201' appears at the RAM error. XX = the high
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top of the display, where order byte of the failing seg-
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XXYY = four hexadecimal ment, e.g.; XX = 20 would in-
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digits. dicate that the error occurred
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between segment 2000 and seg-
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ment 2400. (Memory is tested
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in 16K blocks; each 64K incre-
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ments the segment by 1000.
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YY = the failing bit pattern,
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which can isolate the specific
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RAM).
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6. 'XX 301' appears at the Keyboard error; usually a
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top of the display, where stuck key, where XX = the scan
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XXYY = four hexidecimal code of the stuck key.
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digits.
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7. '131' appears on the display. Cassette port error.
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8. '1701' appears on the IBM Fixed Disk error.
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display.
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9. System beeps; Checksum error in BASIC ROM.
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1 long beep (3 seconds),
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2 short beeps (1 second
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each), and 'ROM' appears
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on the display.
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10. '601' appears on display. Disk drive A, or disk adapter.
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11. 'PARITY CHECK 1' appears. A RAM parity error has occur-
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red on the system motherboard.
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The INT 2 routine in the BIOS
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gains control and HALTs the
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8088 when a memory parity
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error occurs. Parity checking
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had been DISABLED prior to this
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point in the test sequence, and
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is enabled here just before
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reading the boot record from
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the disk.
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12. 'PARITY CHECK 2' appears A RAM parity error has occurred
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on the display. on an add-on memory board. This
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message comes from the BIOS
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ROM's INT routine, which then
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HALTS the 8088.
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13. System beeps: This is normal system response
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1 short beep (1 second). just before the system boots
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from the disk. The system has
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successfully passed the diag-
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nostics.
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