Radio Shack TRS-80 Service Manual page 59

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Phenomen
-4-
Drawing is done
segment by
segment
Condition
2
Abnonnallty Is noticed
regardless of whether the
pen Is moving up or
down.
I Actuator of the electro·
magnet unit
(4·1) is
detached from the
electromagnet coll.
Cause
3
Defonnat1on of ejection
lever shafl unit (4·2).
4
Low battery \'Oltage
I
Foreign matter has
accumulated in the
moving ~ction of the
slider unit.
2 Contact between pen
tape-out lever unit (6·1)
and_.2. e n.
3 Wire fastening position
on bobbin has moved.
4 Improper pulley rotation
of pulley support. base
unit (right).
S
Sfeeve\2-SJ and frame
make contact.
6 X-motor unit (2·1) is
operating improperly.
7
Contact between set-
screw of return spring
and small roller.
1 Current is not l>eing
supplied to the electro-
magnet properly.
Location and Method
of Checklng
Check the contact between the
ejection lever and ejection
roller (4-4).
Check !hat battery voltage i. s
not below 4.5V.
Check that slider unit moves
smoothly on the effective
printing uea and check for an
abnormal load by slowly
rotating the bobbin gear by
hand.
Check contact between pen
take-out lever and slider unit.
Rotate bobbin gear unit (2·3)
by hand and cheek that slider
unit moves smoothly from
left edge to right edge.
Dismount wire from pulley and
check for smooth rotation.
Check fo r deformation
between frame unit and sleeve,
as well as for other phenomena.
Dismount X idle gcar-(2-2}.
slowly rotate motor gear, and
check for abnormal load.
Move slider and confinn
con
I
act
Check if current is going to the
electromagnet,
Repair Method
• Replace ejection lever shaft
unit
Recharge to nonnal voltage
Remove any foreign mailer
Repl0<:e pen take-out lever.
R .. tretch wire if its fmtening
position is wrong.
Replace pulley •upport ba•e
unit.
Replace sleeve.
Replace motor.
• Repalce rotary holder
• Replace paper holding
roller support plate unit.
Replace electromagnet and
repalr drive circuit.
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