IBM 3112, Service Manual

Page: 45 / 184

bh1s.bk : bh1sdiag.doc 29 Thu Apr 20 12:42:16 1995
Diagnostic Information
29
board J15-10. The voltage will change from 0VDC to +5VDC as the
selector lever is moved. Also
see “23 Paper Jams” on page 18.
Paper Feed Problem, E Feeder/
100-Sheet Auxiliary Feeder
Check for the following: paper or envelope jammed in the feed path;
missing hold-down weight; adjustable guide out of position; feeder
cable loose, disconnected, or plugged in the wrong connector; feeder
incorrectly installed; worn or damaged rollers or gears; warped or dam-
aged envelopes used; envelopes improperly installed (envelope flaps
must rest against the paper edge guide); envelopes other than 20 or 24
pound used in the E Feeder; paper other than 20 or 24 pound
used in the 100-sheet auxiliary feeder; envelopes interleaved with
paper.
Run the diagnostics Envelope Feed test and make sure the feed mag-
net is being energized. If not, check the resistance of the magnet at
J10-1 to J10-2 on the feeder cable; the resistance should be from 105
Ohms to 155 Ohms. If the magnet is good, reconnect the cable and
monitor the voltage between the two pins of the connector while running
the Envelope Feed test; if the voltage does not increase momentarily as
the magnet is picked, replace the engine board.
Check the adjustment of the feeder magnet. If paper is being bent or
double-fed, check the adjustment of the feeder restraint spring.
Printhead
Note: The printhead is a sealed unit. It contains no internal parts
that can be replaced or adjusted.
Verify the presence of the following voltages: +24VDC at engine board
J2-1, +5VDC at engine board J11-4, and +5VDC at engine board J12-8.
If these voltages are not correct, replace the engine board.
Verify the continuity of the fan/mirror motor cable, the hsync cable, and
the laser cable.
934 and 935 errors: Check engine board J2-5 during a POR; the volt-
age should be b2VDC and +4VDC for about 7 seconds after
the main motor turns on. If the voltage is incorrect, replace the engine