IBM 6400 Series, Maintenance Manual

Page: 130 / 428

130 Troubleshooting
1. Power off the printer. Open the rear cabinet door. Unload the power stacker.
Move the elevator up and down by hand, checking that it moves smoothly and
without chattering or shuddering.
Eliminate causes of chattering or shuddering. (E.g., loose, damaged, or
broken constant force springs, bent or misaligned rails, obstructions, etc.)
NOTE: If the elevator assembly or the rails are bent or damaged, you must
replace the entire power stacker assembly.
2. Move the elevator up and down by hand. Check that the limit switches are
physically tripped when elevator reaches top and bottom of travel.
If necessary, gently bend the contact arms to adjust limit switches. If you
cannot adjust a switch that requires adjustment, replace it.
3. a) Unfasten the cable clamp holding the stacker control panel cables.
b) Disconnect stacker rail cable connector P107 from connector J3 on the back of
the stacker control panel. (See Figure 61, page 380.)
c) Locate pin 1 of connector P107. (See the cable assembly drawing in Appendix
A, page 327.)
d) Check the stacker rail cable and limit switches for continuity and shorts. Check
continuity of the switch when open and closed. (See the power stacker control
panel PCBA pinout drawing on page 304. STK FULL is the upper limit switch,
STK LIMIT is the bottom switch.)
Replace the stacker rail cable if it is damaged or fails continuity test.
Replace any switch that fails continuity test.
Stacker motor check
NOTE: This procedure tests the four stacker motors and their cables. You
will usually be referred to this procedure from other troubleshooting
procedures. When you have completed this procedure, return to the
procedure that sent you here.
1. a) Power off the printer.
b) Open the rear cabinet door.
c) Unfasten the cable clamp holding the stacker control panel cables.
d) Disconnect stacker rail cable connector P107 from connector J3 on the back of
the stacker control panel. (See Figure 61, page 380.)
e) Disconnect stacker frame cable connector P102 from connector J4 on the rear
of the stacker control panel. (See Figure 61, page 380.)
f) Locate pin 1 of connector P102 and connector P107. (See the cable assembly
drawings in Appendix A, pages 324 and 327.)
g) Check both cables for pin damage, continuity, and shorts. Check all motors for