IBM 3278 Series Maintenance Information page 147

3. If the voltage is less than +44 V, go to step C.
4. If the voltage is greater than +48 V, go to step D.
C. Voltage Measured Is Less fhan +44 V
1. Switch off the 3278.
2. Connect the jumper to pin J5. (See Figure 4-11.)
3. Switch on the 3278.
4. Measure the voltage at fuse 5
(+)
to dc return (-).
5. If the voltage is between +44 and +48 V, the
adjustment is completed. Skip the following steps.
6. If the voltage is still less than +44 V, one or more
of the following conditions are present:
a. The +44 V power supply is defective.
b. The ferrotransformer is defective.
c. There is a logic or cable short.
D. Voltage Measured Is Greater Than +48 V (with
jumper connected to pin J6)
1. Switch off the 3278.
2. Connect the ju mper to pi n J7.
3. Switch on the 3278.
4. Measure the voltage at fuse 5
(+)
to dc return (-).
5. If the voltage is between +44 and +48 V, the
adjustment is completed. Skip the following
steps.
6. If the voltage is still greater than +48 V, go to
step E.
E. Voltage Measured Is Greater Than +48 V (with
jumper connected to pin J6)
1. Switch off the 3278.
2. Connect the jumper to pin J9.
3. Switch on the 3278.
4. Measure the voltage at fuse 5
(+)
to dc return
{-I.
5. If the voltage is between +44 and +48 V, the
adjustment is completed.
6. If the voltage is still greater than +48 V, one or
more of the following conditions may be present:
a. The +44 V power supply is defective.
b. The ferrotransformer is defective.
c. There is a logic or cable short.
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