Print Head Assembly; Head Assembly - Radio Shack TRS-80 Service Manual

C.
ADJUSTMENTS
1.
Covers, Left and
Right
(4, 6)
a.
As you mount
the
left
(4)
and
right
(6)
covers to the
printer base,
be
sure that the covers
align
with
and snap
into
the standoffs on
the
left
and
right sides
of the frame.
D.
PREVENTIVE
MAINTENANCE
1.
Clean
all
cover assemblies with
a
mild
detergent.
3.4
PRINT
HEAD ASSEMBLY
(Figure
3-2A)
REFERENCE
ASSEMBLY
11
1
A.
FUNCTION
PART
NUMBER
62001136-5002
DESCRIPTION
Print
Head Assembly
Print
Head Assembly
QTY.
The
standard
print
head assembly
contains seven
print wires. Since
the
print
wires
are not
attached
to
the
coil
arma-
tures the prmt head
.s
commonly
referred
to
as the
"free
flight
head."
As
the
head assembly
moves
across the
print line
the
seven
print
wires
are
selectively fired to
graphically construct
the characters
in
a
dot matrix
pattern.
B.
REMOVAL/REPLACEMENT PROCEDURE
TOOLS
REQUIRED:
NONE
1.
Remove
the ribbon from
the
print
head
ribbon guides.
2.
Remove
the fingerboard P012
on
the
print
head
cable from connector
J012
on
the video
amplifier.
3.
Release clamping
spring tension, on
the
left
side
of
the carriage
assembly
by
pulling spring up and
over spring
retainer.
4.
Remove
the
print
head
by sliding
off
carriage
assembly towards
the
front of the
printer.
NOTE: RELEASING TENSION
ON
CLAMPING
SPRING WILL ENABLE
PRINT
HEAD
TO
BE
REMOVED WHEN
IN-
STALLING THE
PRINT
HEAD
ASSEMBLY, ENSURE THE CLAMPING SPRING CATCHES THE
LIP
UNDERNEATH
THE
HEAD THEN
PULL SPRING UP AND OVER
SPRING RETAINER
Figure 3-2A. PRINT
HEAD ASSEMBLY
3-6