Adjustment When The Drive Assys Are Replaced - Pioneer PDP-4280HD Service Manual

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8.5 ADJUSTMENT WHEN THE DRIVE ASSYS ARE REPLACED

A
Waveform adjustments required when replacing the following parts of the X DRIVE and Y DRIVE Assys.
Assy Name
X DRIVE Assy
Y DRIVE Assy
B
TIME LAG ADJUSTMENT OF THE CONTROL SIGNAL (SUS-B)
1 Measure the time lag for the SUS-U signal to the SUS-B signal.
2 Check the time lag for the SUS-B GATE signal to the SUS-U GATE siganl.
Adjust the variable control so that the time lag of GATE becomes " time lag of input signal + α ± 5 nsec."
Note: For details on measuring points of waveform, see the figure below.
C
SUS-U signal (input to the DRIVE Assy)
SUS-B signal (input to the DRIVE Assy)
D
SUS-U Gate signal
X DRIVE (GATE terminal of Q1109)
Y DRIVE (GATE terminal of Q2107)
SUS-B Gate signal
X DRIVE (GATE terminal of Q1210)
Y DRIVE (GATE terminal of Q2210)
E
F
134
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2
Ref No. Part Name
IC1101 PS9117AP
IC1104 TND307TD
IC1204 PS9117AP
IC1209 TND307TD
IC2101 PS9117AP
IC2103 TND307TD
IC2201 PS9117AP
IC2203 TND307TD
50 % of the crest value
time lag of SUS-U and SUS-B
Δ Tsus-iub
Time lag of SUS-U Gate and SUS-B Gate : Δ Tsus - gub
Adjust so that "Δ Tsus - gub = Δ Tsus - iub + α ± 5 nsec," using the variable
controls shown in the table below:
Assy
X DRIVE Assy
Y DRIVE Assy
2
3
Part Category
Photo Coupler
FET Driver
Photo Coupler
FET Driver
Photo Coupler
FET Driver
Photo Coupler
FET Driver
50 % of the crest value
time lag of SUS-U Gate and SUS-B Gate
Value of α
VR
VR1002 70 nsec
VR2002 50 nsec
PDP-4280HD
3
4
Remarks
5 V position
5 V position
Δ Tsus - gub
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