Sharp CE-129P Service Manual page 5

Rankirw (A,BorC)
t
<
Printer head ranking position>
After the above procedure,
Kohms protentiometer so that an optimum print quality is
obtalned. The circuit has been so designed as to attain the
best result with the potentiometer
Therefore, existence of aremarkable
might involve the following problems:
1.A>p in head performance
2_~ality change in the termal recording paper
3.
Throuble in the thermal control circuit
1. When VR density Idjustment
A) After replacement has been made in same electronic
component parts inside the solid line.
B) When service request is placed from the user claiming
that print density is too low or high.
2. Print density control method
• Before the print density adjustment,
jumper pad is properly connected
cribed in Table-1.
• The VR should necessarily
mentioned in Fig. 1. If set too much counterciockwise,
it may damage the printhead which mayaiso
omission.
~VR
"-.J
roz-ara
PRINTER UNIT
adjust by means of the 22-
set at its midway_
print density variation
is
needed
make sure that the
as des-
in a manner
be set to the position
cause dot
FiS_'
Do not sale !
• Ensure before the operation of the oscilloscope that the
time axle control knob is set at CALIBRATION.
Adjust the print density in the fOllowing sequence, step 1
thru step 5.
Step 1.
Short the TEST3 jumper pad with a soldering.
t669:>S
Step 2_
Connect the EA-23E AC adaptor with the CE-129P after
the TEST3 pad temperature
temperature, and check the voltage between the JT pad
#9
and pin of the lB1256
(Vp: check)
Step 3.
While observin9 a pulse waveform on the oscilloscope
came from the CLOCK CHECK terminal,
22Kohms VR so that
become the value shown in the graph below.
t669:>S
• Pulse
. - 5-
'1iiOn,
'LJ!I,
_.- I
Solder and sho"
thispo"ion
Fig.2
came down to the room
(Vp) using the voltmeter.
the pulse period
waveform
'3
Fig.
..
~
..
I-
0
2
a:
w
11..
W
~
:)
11..
11
,-,~
(,
~
11
a
•
StE
adjust the
(T) should
StE
@
1. C
c
o
2. S
li
3. ~
C
u
~
1. C
2. S
li
3. S
1.