Adjustment When The Drive Assys Are Replaced; Time Lag Adjustment Of The Control Signal - Pioneer PDP-5020FD Service Manual

1

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: • Be sure to set the Drive to OFF for adjustment.
• 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
X DRIVE (Gate terminal of Q1108)
Y DRIVE (Gate terminal of Q2107)
X DRIVE (Gate terminal of Q1219)
Y DRIVE (Gate terminal of Q2218)
E
F
176
1
2
Ref No. Part Name
IC1101 PS9818-1(P)
IC1104 TND307TD
IC1204 PS9818-2(P)
IC1209 TND307TD
IC2101 PS9818-1(P)
IC2103 TND307TD
IC2201 PS9818-1(P)
IC2203 TND307TD
50 % of the crest value
time lag of SUS-U and SUS-B
Δ Tsus-iub
SUS-U signal
SUS-B signal
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 60 nsec
VR2002 60 nsec
PDP-5020FD
3
4
Remarks
5 V position
5 V position
Δ Tsus - gub
4