5100 Service Tips; General Tips; Tape File Recovery - IBM 5100 Maintenance Information Manual

5100 SERVICE TIPS
DANGER
Do not touch or attempt to remove the coax cable
while the TV monitor is plugged into an AC outlet.
There is the possibility of 110 volts being carried on
the coax BNC connector and the cable shield, if the
TV monitor has not been properly modified by the
user. This voltage could also appear on the frame of
the 5100.
General Tips
• Try to force the failure when running diagnostics by:
Vibrating the machine/cards/connections.
Raising the machine temperature (unplug the
blower).
CAUTION
Do not exceed 20 minutes.
Lowering the machine temperature (use a circuit
coolant).
• Machine power switch must be down (off) when you
remove the read/write storage cards (K2, K4, L2, L4,
M2, M4, N2, N4). All other cards can be removed
with power switch up (on).
• You can remove the following cards/devices if they
are not part of the failing operation or when you are
trying to isolate to a failing operation:
A2-1 /0 cable driver card
B2-Communications card
C2-Asynchronous communication/serial I/O card
APL cards (C2, 02, 04, H4) if the failure is in
BASIC
- BASICcard C4 if the failure is in APL
3-94
Read/write storage cards (K2, K4, L2, L4, M2,
M4, N2, N4)
5103 Printer
5106 Auxiliary Tape Unit
• You can either swap the parts of the internal and
auxiliary tape units, or you can physically or
electrically swap the complete tape units. To swap
electrically, swap the cable in the Z2 socket of the
5100 A1 board with the cable socket in socket B4 of
the Auxiliary Tape Unit. The internal tape unit
address is now E40 (BASIC) or 002 (APL).
Tape File Recovery
This procedure can be used to recover tape files before
and after a defective file (CRCin header). To identify a
defective file, do a UTIL or )UB of the cartridge starting
r\
with file 1. ',,-
j
Use the following example: Files 1 through 4 are good,
file 5 is defective (CRC in header), files 6 through 10 are
good. By using the normal load and save commands,
you can save files 1 through 4. When file 5 is reached
(defective file). remove the cartridge and manually move
the tape forward past a load of the file 6, and repeat
the load and save operations for fields 6 through 10.
(Be sure to save to a different tape and mark as
required.) By marking file 4 on the defective tape one K
larger than it was, you can reuse the tape. All files past
file 3 are now lost.