IBM 3112, Service Manual

Page: 33 / 184

bh1s.bk : bh1sdiag.doc 17 Thu Apr 20 12:42:16 1995
Diagnostic Information
17
feed roll or transfer roll. Also see Banding.
Inspect the HVPS contacts; make sure each spring-loaded contact
returns when pressed and released. Inspect the transfer roll housing
contacts for damage or contamination. Check the gear train for dam-
age, binds, or wear.
When using the 100-sheet auxiliary feeder, some blurring may occur at
the point where the feeder’s friction rollers release the paper.
Dead Machine
Possible causes: no voltage reaching the printer, LVPS failure, blown
LVPS fuse, failure of the On/Off switch or switch linkage, or a shorted
electrical component.
Check for the indicated voltages at the LVPS connection to the engine
board. If no voltages are present, remove the LVPS cover and check
fuse F1 and the power switch before replacing the LVPS.
If some voltages are present but all are not correct, disconnect all
cables except the LVPS from the engine board. POR and verify that the
LVPS voltages are correct. Turn the power back off and, one at a time,
reconnect the engine board cables, powering on in between each con-
nection and checking the voltages. The connection which causes the
voltages to be wrong indicates which component is bad. Repair or
replace the failing component or cable as necessary.
Duplex
The duplexer should home — the front shafts should turn and the input
deflector should move — immediately when you install the duplexer
with the printer already powered on, or just before the [Ready] screen is
displayed when you POR the printer with the duplexer installed. This
means the duplexer and the printer are communicating and thus the
printer engine board, duplexer system board, and the cables between
them are all good.
Note: With twinax and coax printing, the printout is always simplex
unless the job specifies duplex. (There is no network-duplex menu
item like the 391x had.)