Remote Computer Analysis; Locating Defective Ram Boards - HP 9000 Series 360 Service Handbook

Remote Computer Analysis
The Model 360/370 computers provide for remote analysis of problems
by means of the beeper. To test the computer remotely, follow this
procedure:
1. Establish a telephone connection with someone at the location of
the computer.
2. Have them hold the receiver near the speaker output of the
computer. The speaker is located in most monitors, or in the
speaker module.
3. Now have them turn the computer on.
4. The computer will go through its self-test and report problems as
a series of beeps. These beeps correlate with the above error codes.
5. A high beep indicates a one and a low beep indicates a zero.
For example, suppose that on power-up a computer emits three low
beeps, a high beep, two low beeps and a high beep. This will be of the
form
000 .00.,
where
0
represents a low beep, • represents a high beep
and x represents an unbeeped high or low. Referring to the table of
Boot ROM Error Codes shows a RAM Failure as the probable cause.
Locating Defective RAM Boards
Remember that RAM is on the Model 360 processor board in addition
to the Mbyte RAM assemblies.
A RAM failure message may be decoded to determine which RAM block
caused the failure. For example, in the message
Memory Failed at FFB3A900
W:F58A8C2C.R:F78A8C2C
the failure occured at memory address FFB3A900. To correlate this
with a RAM board, take the first three hex digits of the address and
translate them into binary. Then find a board whose address switches
are set to the first ten bits of the top address in that 4 Mbyte address
block.
Troubleshooting
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