Radio Shack TRS-80 Service Manual page 58

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Phenomcn
- 1- Does nol draw
lines
-2-
Lateral lines
cannot be drawn.
- 3- Insufficient
uteral
Movement
Condition Cause
X-motor(2-l). Y.motor(3-l), Pen (S-1 to 4) have come off,
and pen dri,•e electromagnet or I.he ink is exhausted.
(4-1) operaie normally, but
no printing Is done.
I
X·mo1or
(2-1)
doe.s no t I
X·1notor J e3d wire
is
cut
rotate.
2 Idle gear (2-2) is
deformed.
3 Deformation of bobbin
gear unit (2-3), misalign-
mcnt of two-piece teeth.
4 Foreign mactcr has
accumulated between
_gears
s
Low
battery voltage
6
Slider unit (4·5) does
not slide properly on
the shall.
2 x ~motor rotates, but
I
Wire hos come off
slider unit does not
move to the right or left.
2
Wire is cut.
3 Dobbi. n gear and wire
slip.
4 Gear is damaged
I
Opcnues in pen-down
I Rubber roller uni.t (3-3)
mode only, and not
i1 scratched.
normal.
2 Print paper has steps.
Note: Flgu1e in ( ) is reference number of part.
Loealion and Method
ofChtcking
Are I.he pens mounted pro-
perly?
Do
the pens ha>-e
enough ink?
Check tha1 a normal current is
impressed to each phase of the
nlotor.
Check If
the X idle gear is
normal.
Dismount wire unit
(24),
rotate bobbin gear by hand,
and check rotation state.
Rotate bobbin and unit by
hand and check for foreign
Jnatter
Check If battery voltage is
below 4 .SV.
Disrnount wire and move
slider unit to the right and
ltfl by hand.
Check
if
wire has come off
bobbi~ar.
Check that wire has not been
CUL
Confirm that wire is properly
screwed o n to bobbin gear.
Check that X idle gear and
bobbin gear are operating
properly.
Slowly rotate the rubber roller
by
hand a. n d cheek fo r scratches
and forei, g n matter.
Check the surface of the print
paper
Rtpair Method
Mount properly. Replace I.he
pens.
Replace X·motor.
Replace lhe X idle gear.
Replace bobbin gear unit.
Remove foreign matter.
Recharge to regular voltage.
• Replace sUde unit
• Remove foreign matter
if
it is obstructing mo\-ement.
Restretch wire properly.
Replace wire unit.
• Tighten the screws.
• Replace the bobbin gear
unit.
• Replace damaged gear.
• Replace rubber roller unit if
scatehes are fou nd.
• Remove foreign matter.
Use nonnal print paper.
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