Key Module Replacement - IBM 3278 Series Maintenance Information

2. Lift the circuit board from the all-keys assem-
bly, and place the circuit board on its base in a
clean area.
3. Handle the all-keys assembly by the sides. Be
careful not to press any keys. Lift the all-keys
assembly off the base, turn it over, and place it
on the base_
Note: Swap the key module if the flyplate comes
off. Do not attempt
to
repair the mOdule. Re-
paired modules can cause intermittent failures.
4. Press down on the key module until it is free of
the holding plate.
5. Lift the edge of the all-keys assembly nearest
the key module that has just been removed.
Remove the bad module.
6. Lift the all-keys assembly by the edges, and
invert it on its base.
6.7.6.2 Key Module Replacement
1. Ensure that the alignment tab and the angled key-
stem are in the same position as those of the
other modules in the all-keys assembly.
2. Install the new module (PN 1748131) by press-
ing the key module into the holding plate by
hand.
3. Clean the printed circuit board by carefully
wiping it with a lint-free cloth moistened with
isopropyl alcohol. Inspect all key module fly-
plates for any foreign matter, and carefully
clean if needed.
4. Align the holding screw holes through the base-
plate, circuit board, insulator, and top insulator
(if used). Lower the circuit board assembly
on the all-keys assembly. Secure the circuit
board to the all-keys assembly with the holding
screws.
5. Reinstall the keyboard assembly on the base,
maintaining its original alignment.
6. Reinstall the key button in the correct location.
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