Sharp FO-1460, Service Manual

Page: 82 / 108

2-2. Scan optical system adjustment
(1) Outline
The adjustment procedures of the scan optical system are described
below:
(2) Adjustment procedures
1
Switch off the machine and disconnect the AC power cable from
the wall socket.
2
Fully open the upper cabinet, remove the fixing screws of the
recording paper tray and remove the recording paper tray. In
order to perform a focus adjustment, remove the optical system
unit from the frame.
3
Disconnect the main PWB from the TEL/LIU PWB.
4
Connect your oscilloscope channel 1 to the VIN signal and chan-
nel 2 of your oscilloscope to
φ
T signal (Refer Pin 4 of connector
CNCCD on the main pwb). Connect the earth clips of either probe
to AG ground as shown. Set the trigger to channel 2.
5
Re-connect the main PWB to the TEL/LIU PWB and connect
these circuit boards to the connectors on the chassis.
6
Re-assemble up to and including the recording paper tray to the
main chassis and close upper cabinet.
7
Plug the AC power cable into the wall outlet and turn the fax
machine on.
8
Insert a test chart in the document hopper and execute the CCD
Adjust Mode diagnostic. Press the START key to enable local
copy until approximately one fifth of the page has been copied,
then press the STOP key to enable the CPU wait state.
9
Fully open the upper cabinet and remove the recording paper tray.
F
Install the scan adjustment jig to the optical system unit, so that
the pattern surface is on the lower side.
G
Fit the pins of the scan adjustment jig to the holes of the optical
system frame.
H
Lightly loosen the red screws of the CCD PWB and obtain the VID
signal waveform in synchronization with
φ
T signal waveform. Ad-
just the CCD PWB positioning to obtain the waveform as shown
below.
CCD waveform
I
After completing the CCD adjustment, tighten the two red screws
on the CCD pwb and apply screw locking material to prevent the
CCD pwb from moving.
J
Assemble the recording paper tray and fixing screws.
Optical system
unit
Scan adjustment jig
Reference surface
CNCCD
VO CNCCD-3 (CCD source output)
øT CNCCD-6 (Line sync signal)
VG CNCCD-5 (Ground)
VIN
1.89msec
0.5msec/DIV
VIN
(CH1)
1V/DIV
R
ø
T
ø
T
(CH2)
*1: Difference
*2:White level
*2: Black level
*1: Increase the difference
by focus adjustment.
*2: Adjust as shown by
CCD PWB adjustment.
[CCD waveform model]
UX-510U/UX-510C/UX-500U
UX-500C/FO-1460U
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