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PREVENTIVE MAINTENANCE
CAUTION
Remove power before performing PM or removing
keyboard.
Perform preventive maintenance to the keyboard during
unscheduled interruptions when possible.
If
unscheduled
interruptions do not occur in a twelve month period, a
preventive maintenance schedule must be provided. The
keyboard can be removed from its mounting (remove
power first) for easy servicing. Cable connections on the
left and right sides of the keyboard, and plug-on connectors
for the drive card, make removal easy.
Lubrication
Always lubricate with number 23 grease .. Grease the
following points every twelve months:
• Keylevcr pivots
• Keylever leaf and return springs
• Front interposer guide combs
• Space bar shaft pivots and keylever tab
• Dobber pivots
• Space bar pivots
• Restore bail armature pivots
• Reset drive spring anchors
• Latch spring and momentary link connections
• Interposer latch spring tips
• Shift bar shaft pivots
Cleaning
Clean the unit before each
lubri~ation
and when the environ-
ment indicates it is necessary.
MAINTENANCE
CAUTION
In localing troubles in the circuit portion of the keyboard,
do not use a test light; it could cause damage to the
circuits. Also when using an ohmmeter, take care to
prevent shorting pins or overloading the circuits. Do
not use the ohmmeter on less than R X 100.0 scale.
Part 2. Maintenance
Maintenance consists of adjusting mechanical parts and
replacing worn parts. When troubles are in the encode
board or the magnet driver card, these items must be
replaced. Trouble with the EDS may require replacing
the separator and the diaphragm, or adjusting or replacing
the actuator or the latch spring.
Test points for troubleshooting EDS switches and the
encode board are in the keyboard logics for the using
system.
CHECKS, ADJUSTMENTS, AND REMOVALS
Key Lever
Checks
The keylever, when pressed, should move around its pivot
at the rear of the keyboard until the lever bottoms in the
front guide comb. When released, it should rise until the
lever strikes the up stop rod in the front comb (Figure 2-1 ).
The <lobber should clear the interposer and should return
to its rest position above the interposer projection when
the key is released.
Note:
Unused key positions require their elastic
diaphragm switches to be either open or closed. If
the switches are to be held open, the keylevers are
blocked by a plastic lockout (Part 5994922) to prevent
the operation of the interposer. Closed switches do not
have interposers and are held closed continuously by
the latch spring assembly.
Adjustment
There is no keylever adjustment to meet keylever travel
called for in the checks. Failure to meet these conditions
indicates some defect in the keylever operation or with
the associated mechanisms. Refer to the diagnostic
flowchart in Appendix A or the diagnostic flowchart for
the specific system. For <lobber clearance, refer to
"Adjustment-Latch Key".
Removal
1. Loosen the two front and the two rear encode board
mounting screws, and tilt the board to the rear of the
keyboard (old style only).
2. Remove keybutton from the keylever that is to be
replaced.
3. Remove other keybuttons that extend over the
keylever that is to be replaced.
Elastic Diaphragm Enc Kybds and 5475 Data Entry Kybd
(3/71)
2-1
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