Sony DPP-MS300E, Service Manual

Page: 22 / 88

4-3
POWER SUPPLY BLOCK
[Head Voltage Adjustment]
Before performing this adjustment, print the stair-step pattern
(Note 2) two times continuously with the old head (Note 1) or
normal unit. The second print will be used as a sample of the print
density.
Note 1:
Only when the old head (faulty head) is not entirely damaged
with black or white lines.
Note 2:
To print the stair-step test pattern, turn on the power switch while
pressing the S1707 (CAPTURE) and S1717 (ENTER) on the SW-
40 board.
(Press the S1707 (CAPTURE) and S1717 (ENTER) until a peep
is heard.) Set the S1701 (Rotaly switch) to the position, and
press the S1706 (print), then the print will start.
Adjustment Procedure:
(1)
To print the stair-step test pattern, turn on the power switch
while pressing the S1707 (CAPTURE) and S1717 (ENTER)
on the SW-40 board.
(Press the S1707 (CAPTURE) and S1717 (ENTER) until a
peep is heard.) Set the S1701 (Rotaly switch) to the posi-
tion, and press the S1706 (print), then the print will start.
(2) After printing, repeat (1) immediately.
(3) Compare the second printed pattern density with that of the
sample, and if the density differs, perform the following ad-
justment.
(4) Adjust VR201 according to the print density.
If darker than the sample: Decrease the head voltage.
If lighter than the sample: Increase the head voltage.
(5) Print the stair-step pattern two times continuously.
(6) Compare the second printed pattern density with that of the
simple, and if the density differs, repeat steps (3) to (6).
Note: Only one print is required after the second time.
(7) Turn off the power switch.
Mode Test mode (Note 2)
Signal Test pattern (Stair-step)
Measuring points
+: CN1943
2
pin (MD-40 board)
–: CN1943
3
pin
Measuring instrument Digital Voltmerter
Adjustment part VR201
Specification Print density should be the same as the sample
Fig. 4-4 Stair-step pattern
* VR201 is in the power block (1-468-364-51).
Adjustment Location:
power block
VR201