Radio Shack TRS-80 Service Manual page 61

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Phenomen
-5- Color does not
I
Change
2
3
4
s
6
Condition
Pen moves to color
change area without
moving up.
Curiage does not
move until
it
reaches
the left edge.
Rotary holder does not
rotate at
all.
Rotary holder rotates not
only counterclockwlse,
but also clockwise.
Rotary holder makes
excessive rotations
Rotary holder romlon
is bad only for the first
mo\·ement afte1 resetting.
Cause
I Electromagnet induced
pen up function is
abnormal.
I Foreign matter has
accumulated in slider
section.
2
Contact between slide
shafi suppon plate
and frame
I
Fatigue and deformation
of color change click
(4·7).
2
Pen tip has come off the
r<tum spring.
3
Pen return spring is
deformed.
4
Holder stopper inside
slider unit does not
operate well.
I Deformation of hooking
click
I
Deformation of paper
guide.
2 Tresence ot foreign
matter.
I
Slider unit is misaligned
Location and Method
of Checking
Check transmission system
from electromagnet to pen
drive.
Check for foreign mailer.
Check if slider moves smoothly
by rotating the bobbin gear
by hand.
Check for contact.
Check color change click
Check
all
four pens to see if
they have come off.
Check the shape of the pen
return spring
Check holder slop operation.
Check if hooking click and
rotary holder ratchet are
making proper contact.
Check for contact between
paper gulde and pen
tip.
Check forToreign matter.
Check stop sections of slider
and wire.
Repair Method
See Phenomenon 4
Remove foreign maner and
exchange slider unit .
Replace slider unit.
• Gently lift color change
click ullng tweezers.
• Replace color change click.
• Repair using tweezers.
• Replace rotary holder if
return spring Is deformed.
• Rcp!iice rotary holder.
Replace slider unit.
Replace slider unit.
• Adjust pen stroke.
• Replace printer.
Remove foreign matter.
Adjust relative postions of
slider and wire
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