IBM 5100 Maintenance Information Manual page 173

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Symptom
003 through 010 intermittent errors.
003 and 004 errors when marking
new tapes.
003, 004, and 007 errors.
003, 004, 007 and 008 errors.
004 and 007 errors on diagnostics
and customer jobs.
004 and 007 errors.
004,005, 006, 007, and 008 errors.
004, 007, and 008 errors.
007 errors.
Isolation Aid
Check the customer grounding and
the 5100 grounding.
None.
Check for bad solder connections at
paddle cards and cable connectors.
Also check for strands of wire
shorting to pins.
None.
Moving the cable that goes to the
CRT away from the tape control card
causes the problem to disappear.
Loose read/write head.
The customer usually sees only 005
errors, but can create 007 errors
unknowingly.
Locking wheels are not centered or
seated properly in the base.
Excessive retries.
Fix
Check to see if customer is using an
ungrounded extension cord.
Replace the LED/PTX assembly.
Replace or repair the cables and verify
that all connections are good.
Replace the H2 card.
Replace the CRT.
Replace the read/write head.
Adjust tape microswitches for a
clearance of 0.001 inches (0.025 mm)
to 0.003 inches (0.076). Adjust for
maximum overtravel.
Adjust the locking wheels (see 225)
and check the adjustment by pulling
the cartridge out about 1/8 inch (3
mm) and releasing it. The cartridge
should seat in the tape unit.
Check the select magnet and the
jackshaft adjustments. (See 222 and
223.)
The motor locks up or does not move Replace the motor.
the tape properly.
The tape rubs against the cartridge
base plate or plastic top.
Extra bytes are written in the data
record filed on the diagnostic tape
cartridge during a CMD 0 or CMD 1.
Reposition the tape on the spools by
doing a )LlB or UTIL; then mark a file
to the end of tape and do a rewind.
Check out the tape by doing a )LlB or
UTIL on the diagnostic tape cartridge.
If this works, load the failing file
using the CMD 8 function.
If there is an error in the data, an 007
error will be displayed. You can
rebuild the damaged file using a
known good tape and CMD 8 and
CMD 9 procedures.
The display is not blanked during tape IN PROCESS and PROCESS CHECK
operations. leads are swapped. (See 210 for
correct wiring).
Intermittent Failures Troubleshooting Guide 3-91