Pioneer PDP-502MX Service Manual page 72

PDP-502MX, PDP-502MXE
Procedure Adjusting Item
VOFS/VH/
7
VRN/IC5V
Voltage adjustment
Note) Be sure to measure between specified test points.
Sustain Pulse
8
Waveform
adjustment
72
Input signal Adjusting Point
VR701 (VOFS)
Y DRIVE ASSY
VR751(VH)
Y DRIVE ASSY
White 100%
signal
VR801 (VRN)
Y DRIVE ASSY
VR851 (IC5V)
Y DRIVE ASSY
DRIVE ADJ mode
in Factory mode
X-SUS-G......."2" Key
Y-SUS-G ......"4" Key
DRIVE ADJ mode
in Factory mode
X-SUS-B......."1" Key
Y-SUS-B ......"3" Key
White 100%
signal
Adjusting Method
VOFS (Offset voltage) adjustment
Adjust so that the voltage between K702 (VOFS) and K701 (SUS GND)
becomes ± 0.5V" of the voltage indicated at the "voltage indication
label".
The symptom in case of mis-adjustment
If the VOFS adjustment is not performed properly, dots like blinking
luminance points appear. If deviated greatly from the right adjustment
point, Panel will light white.
VH (voltage for Scan IC) adjustment
Adjust so that the voltage between K753 (VH) and K752 (PSUS)
becomes "85V ± 0.5V".
PSUS (=GNDH) is a floating GND and the electric potential is different
from that of chassis GND. Be sure not to short-circuit PSUS (=GNDH)
and another GND, because that may damage the unit.
The symptom in case of mis-adjustment
If the VH adjustment is not performed properly, dots like blinking
luminance points appear. If deviated greatly from the right adjustment
point, panel will light white.
VRN (Minus Reset voltage) adjustment
Adjust so that the voltage between K802 (VRN) and K803 (RN. GND)
becomes "-200V ± 0.5V".
The symptom in case of mis-adjustment
If the VRN adjustment is not performed properly, dots like blinking
luminance points appear. If deviated greatly from the right adjustment
point, Panel will stop lighting.
IC5V adjustment
Adjust so that the voltage between K851 (IC5V) and K855 (PSUS)
becomes "+5.0V ± 0.1V".
PSUS (=GNDH) is a floating GND and the electric potential is different
from that of chassis GND. Be sure not to short-circuit PSUS (=GNDH)
and another GND, because that may damage the unit.
X-SUS-G, Y-SUS-G adjustment
Set to the indicated value with a key on the remote control unit.
(refer to DRIVE ADJ mode)
X-SUS-B, Y-SUS-B adjustment
1) Set adjustment value to "8", and confirm that green mis-discharging
dots do not appear within 20mm from top & bottom of Screen.
2) When green mis-discharging dots appear, decrease the adjustment
value "1" by "1" until green mis-discharging dots will disappear.
Set the adjustment value when the green disappear.
3) Observe sustain waveform at each Drive Assy, between K3454
(X-PSUS) and K3455 (SUS-GND), and K3701 (Y-PSUS) and
K3605 (SUS-GND). Confirm that the waveform is not distorted.
The symptom in case of mis-adjustment
Green mis-discharging dots
appear within 20mm from
top & bottom of Screen.