IBM 5256-1 Maintenance Information Manual page 109

193
ERROR CODES, LIGHTS, SWITCHES, AND
TEST POINTS (CONTINUED)
Wire Check (Light 1 )-When the part of the printer logic
on the voltage regulator card or planar recognizes that a
wire has been on too long, the logic activates the 'wire
check' line. This line causes the Wire Check light to
come on and all printer functions to stop for
1/2
second. The printer logic activates the 'printer reset'
line. If the reset does not clear the wire check, the logic
signals a hard error by turning on the Unit Check and
Attention lights.
Slows Speed Check (Light 2)- The slow speed check
occurs when 50 consecutive emitter pulses occur that
'exceed the maximum allowable spacing:
40 cps
80 cps
120 cps
3.45 ms
2.08
ms
1.50 ms
This error by itself is always a soft error and no '
recovery is attempted. However, the error might appear
hard if it occurs with a hard error. Generally, the only
reason for the soft error light is that the last emitter
pulse received exceeded the slow speed maximum
spacing and was followed by a hard error. See also
Emitter Sequence and No Emitters.
Fast Speed Check (Light 3)-The emitter pulses must
conform to the following minimum spacing:
40 cps
80 cps
120
cps
728
ms
700 ms
500
ms
If a second emitter pulse occurs within the spacing, it is
considered a fast emitter pulse (fast speed check). Light
3 will not turn on unless the condition occurs on two
consecutive emitter pulses. If this happens, light 3 is
turned on and the logic performs an automatic retry. If
the same condition occurs again on two consecutive
emitter pulses during the retry, a hard error results.
Emitter Sequence (Light 4)-This error occurs for any of
the 3 following conditions:
1.
2.
An emitter pulse occurs in the wrong sequence for
the direction the carrier is moving.
An emitter pulse was missed because the pickup
failed or the pulse came on too soon after the
previous pulse.
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3. All 3 emitter pulses were on (or off) at the same
time. This kind of emitter sequence error is the
only one that can occur during the stop-time
turnaround.
If lights 3 and 4 are both on, the emitter pulse probably
was early and so short that it was gone before the fast
speed check (minimum spacing) occurred. If lights 2
and 4 are both on, the emitter pulse probably was not
detected (the pulse did not occur).
No Emitters (Light 5)-:-Light 5 turns on for either of the
following conditions:
1.
2.
The processor does not recognize an emitter pulse
after 125 ms.
The processor senses the emitter pulse, but the
hardware does not provide the timing checkpoints
for minimum spacing.
If lights
3
and
5
are both on, two pulses occurred too
close together and no more pulses were recognized. If
lights 2 and 5 are both on, the last 2 emitter pulses
were too far apart and no pulses were recognized.
Overrun (Light 6)-lf the minimum spacing checkpoint is
not handled by the processor before the hardware
reaches the next minimum spacing point, the processor
has been overrun by the hardware. This indicates:
1.
2.
Something kept the processor from servicing the
emitters.
The processor failed for a time.
Forms Stopped (Light 7)-Light 7 turns on if the forms
logic was started but no activity occurred for 250 ms.
If the forms move from the detent position by 1 motor
phase when the printer is ready, the processor attempts
to move it back to the correct position. If this action is
not completed in 250 ms, light 7 turns on.
Forms Position Check (Light B)-Light 8 is turned on if
the forms move from the detent position by more than 1
motor phase when the Ready light is on.
Forms overrun occurs if the processor fails to service
the forms logic. If this happens, forms motion is
stopped and light 7 or 8 (or neither) might be on
(depending on the condition within the processor).
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