Pioneer PDP-503PC Service Manual page 68

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1
SUS-B Ground Timing Adjustment
It is necessary to readjust this adjustment when replaced the X or Y DRIVE Assy and the pulse module.
A
Measurement point and method
Measurement point of waveform of X and Y DRIVE Assy in timing adjustment is test pin of SUSOUT of the pulse module of
bottom of the main unit.
X DRIVE Assy : K3106
Measurement screen : White mask
The measurement is easy to perform when turns field AB alternation to OFF. (RS-232C command: OCN)
Measure a sustain pulse of the fourth pulse (X DRIVE) and the fifth pulse (Y DRIVE) from the back of the fourth FS, and
adjust. In the start section of this sustain pulse, waveform has inflection point with the timing when SUS-B becomes ON.
Adjust so that the voltage of this inflection point is the nearest to 150V and do not become less than 150V.
Adjustment parameter
X DRIVE: XSUSB (RS-232C command : XSB)
B
Y DRIVE: YSUSB (RS-232C command : YSB)
Note:
• Connect a GND probe to the SUSGND terminal to measure the waveform.
If this is not done there may be errors in adjustment.
Waveform in the measurement
C
D
E
150V Line
GND
F
68
1
2
Y DRIVE Assy : K2203
Rst
1ms/div
Magnify 4SF block
X
Y
X
5µs/div
Magnify the fourth pulse sustain pulse (XSUSOUT waveform) from the back of the above waveform.
100msec/div
50V/div
This broken section moves by
changing the adjustment
parameter.
PDP-503PC
2
3
1SF
2SF
3SF
4SF
Y
X
Y
X
Y
X
Y
X
Y
Measure a waveform of this section and adjust.
150V Line
3
4
CH1 : Y SUSOUT (K2203), 50V/div
CH2 : X SUSOUT (K3106), 50V/div
CH4 : YPR-U1 (K2038)- Trigger, 5V/div
Trigger : 2msec delay
100msec/div
50V/div
Become less than 150V.
→ NG
4

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