Sharp FO-1470 Service Manual page 83

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 record-
ing paper tray and remove the recording paper tray. In order to per-
form 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 channel 2
of your oscilloscope to 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.
CNCCD
VO CNCCD-3 (CCD source output)
øT CNCCD-6 (Line sync signal)
VG CNCCD-5 (Ground)
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 sys-
tem frame.
VIN
8 – 3
H
Lightly loosen the red screws of the CCD PWB and obtain the VID
signal waveform in synchronization with T signal waveform. Adjust
the CCD PWB positioning to obtain the waveform as shown below.
Reference surface
1V/DIV
ø
R T
1.89msec
*1: Difference
[CCD waveform model]
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.
UX-510UA
FO-1470U
Scan adjustment jig
Optical system
unit
VIN
(CH1)
ø
T
(CH2)
0.5msec/DIV
*2:White level
*1: Increase the difference
by focus adjustment.
*2: Adjust as shown by
CCD PWB adjustment.
*2: Black level