Diagnostic Output And Beep Codes - NEC POWERMATE 4100M Service Manual

4-10 Maintenance and Troubleshooting

Diagnostic Output and Beep Codes

One beep indicates that the computer has completed its power-on self-test. If intermittent
beeping occurs, power off the computer and try again. If the beeping persists, see Table
Section 4-4 for diagnostic outputs and beep codes.
The diagnostic port output codes are placed at the diagnostic status port (port 80) to indi-
cate tests in progress and failed tests to someone with hardware that can detect the output.
If the FAILBEEP option is selected, the BEEP CODES are announced on the speaker only
if a fatal failure is detected. For instance, "2-1-4" (a burst of two beeps, a single beep, a
burst of four beeps) indicates a failure of bit 3 in the first 64 K of RAM. Both sets of codes
are only used prior to screen initialization and screen retrace verification. Once the screen is
believed operable, diagnostic reporting is via screen messages, except if MANLOOP EQU
TRUE and the jumpers say to loop on POST. In this case, it is assumed that no video
adapter is attached and some additional errors are reported via the diagnostic port and the
speaker.
Table Section 4-4 Diagnostic Output and Beep Codes
Diagnostic Port Output
EB_PDIF EQU0400h
E_REGS EQU 01h
E_CRAM EQU 02h
E_BROM EQU 03h
E_TIMR EQU 04h
E_DMAI EQU 05h
E_PAGE EQU 06h
E_REFR EQU 08h
E_RAM0 EQU 09h
E_MMUL EQU 0Ah
E_MOEL EQU 0Bh
E_MADD EQU 0Ch
E_RAMP EQU 0Dh
E_FSTIMR EQU 0Eh
E_NMIIO EQU 0Fh
E_MBIT EQU 10h
E_MBIT EQU 11h
E_MBIT EQU 12h
Beep Codes Description of Test or Failure
Pointing device interface failure (mouse)
80486 register test in progress
1-1-3 CMOS write/read test in progress or failure
1-1-4 BIOS ROM checksum in progress or failure
1-2-1 Programmable Interval Timer test in progress or
failure
1-2-2 DMA initialization in progress or failure
1-2-3 DMA page register write/read test in progress or
failure
1-3-1 RAM refresh verification in progress or failure
1st 64 K RAM test in progress
1-3-3 1st 64 K RAM chip or data line failure
1-3-4 1st 64 K RAM odd/even logic failure
1-4-1 1st 64 K RAM address line failure
1-4-2 1st 64 K RAM parity test in progress or failure
1-4-3 Fail-safe timer test in progress
1-4-4 Software NMI port test in progress
2-1-1 1st 64 K RAM chip or data line failure - bit 0
2-1-2 1st 64 K RAM chip or data line failure - bit 1
2-1-3 1st 64 K RAM chip or data line failure - bit 2