How to troubleshoot the Y SUS board of a LG 50PJ350 Plasma TV
Y-SUS
Board develops the V-Scan drive signal to the Y-Drive boards.
•
Adjustments
• DC Voltage and Waveform Checks
• Diode Mode Measurements
• DC Voltage and Waveform Checks
• Diode Mode Measurements
Operating Voltages
SMPS
Supplied
VA
VS
M5V
VS
M5V
VA
supplies the Panel’s Vertical Electrodes (Routed to the Left X-Board)
VS Supplies the Panel’s Horizontal Electrodes. Also routed to the Z-SUS board.
M5V Supplies Bias to Y-SUS. (From Y-SUS routed to the Control Board then Z-SUS)
VS Supplies the Panel’s Horizontal Electrodes. Also routed to the Z-SUS board.
M5V Supplies Bias to Y-SUS. (From Y-SUS routed to the Control Board then Z-SUS)
Y-SUS
Developed
VY
VR502
VSC VR501
V SET UP VR401
V SET DN VR402 16V
VSC VR501
V SET UP VR401
V SET DN VR402 16V
-VY
Sets the Negative excursion of reset in the Drive Waveform VSC Sets the
amplitude of the complex waveform.
SET UP sets amplitude of the Top Ramp of Reset in the Drive Waveform
SET DOWN sets the Pitch of the Bottom Ramp for Reset in the Waveform
Used internally to develop the Y-Drive signal. (Also routed to the Control Board then routed to the Z-SUS board)
SET DOWN sets the Pitch of the Bottom Ramp for Reset in the Waveform
Used internally to develop the Y-Drive signal. (Also routed to the Control Board then routed to the Z-SUS board)
Floating
Ground
FG
5V
FG 15V
FG 15V
Used
on the Y-Drive boards (Measured from Floating Gnd)
Used in the Development of the Y-Drive Waveform (Measured from Floating Gnd)
Used in the Development of the Y-Drive Waveform (Measured from Floating Gnd)
VSC and -VY Adjustments
CAUTION:
Use the actual panel label and not the book for exact voltage settings.
These
are DC level Voltage Adjustments.
Set
should run for 15 minutes, this is the “Heat Run” mode.
Set screen to “White Wash”.
1) Adjust –Vy VR502 to Panel’s Label voltage (+/- 1V)
2) Adjust VSC VR501 to Panel’s Label voltage (+/- 1V)
Set screen to “White Wash”.
1) Adjust –Vy VR502 to Panel’s Label voltage (+/- 1V)
2) Adjust VSC VR501 to Panel’s Label voltage (+/- 1V)
Y-Drive Signal Overview
Y-Drive
Lower Test Point (Top Buffer)
Finding on to the Y-Drive Waveform Tip
Note,
this TP (VS_DA) can be used as an External Trigger for scope when locking onto the
Y-Drive (Scan) or the Z-Drive signal.
This
signal can also be used to help lock the scope when observing the LVDS video
signals.
Observing (Capturing) the Y-Drive Signal for Set Up Adjustment
Set
must be in “WHITE WASH”
All other DC Voltage adjustments should have already been made.
All other DC Voltage adjustments should have already been made.
Fig
1:
As an example of how to lock in to the Y-Drive Waveform.
Fig 1 shows the signal locked in at 2ms per/div.
Note the 2 blanking sections.
The area for adjustment is pointed out within the Waveform.
As an example of how to lock in to the Y-Drive Waveform.
Fig 1 shows the signal locked in at 2ms per/div.
Note the 2 blanking sections.
The area for adjustment is pointed out within the Waveform.
Fig
2:
At 200uSec per/division, the area of the waveform to use for SET-UP or SET-DN is now becoming clear.
Now the only two blanking signals are present.
At 200uSec per/division, the area of the waveform to use for SET-UP or SET-DN is now becoming clear.
Now the only two blanking signals are present.
Fig
3:
At 100us per/div the area for adjustment of SET-UP or SET-DN is now easier to recognize. It is outlined within the Waveform.
Remember, this is the 1st large signal to the right of blanking.
At 100us per/div the area for adjustment of SET-UP or SET-DN is now easier to recognize. It is outlined within the Waveform.
Remember, this is the 1st large signal to the right of blanking.
TIP:
If you expand to 100uSec per/division, the adjustment for:
SET-UP can be made using VR402 and the
SET-DN can be made using VR401.
It will make this adjustment easier if you use the “Expanded” mode of your scope.
SET-UP can be made using VR402 and the
SET-DN can be made using VR401.
It will make this adjustment easier if you use the “Expanded” mode of your scope.
Set Up and Set Down Adjustments
Set Up Adjustment Too High or Low
Y-SUS Board Troubleshooting VScan.
Y-SUS
Board develops the V-Scan drive signal to the Y-Drive boards.
This Section of the Presentation will cover troubleshooting the Y-SUS Board.
Warning: Never run the Y-SUS with P212 (Y-SUS) or P204/P110 (Y-Drives) removed unless the Y-Drive boards are removed completely. Board Failure will occur.
This Section of the Presentation will cover troubleshooting the Y-SUS Board.
Warning: Never run the Y-SUS with P212 (Y-SUS) or P204/P110 (Y-Drives) removed unless the Y-Drive boards are removed completely. Board Failure will occur.
TIP:
Use the Scan Output Screw Lugs to test for
V-Scan signal if the Y-Drive boards are removed.
V-Scan signal if the Y-Drive boards are removed.
Y-SUS Board P212 Connector to P205 Lower Y-Drive (Logic and FG5V
TIP:
Connectors do not come with a new Y-SUS or Y-Drives
Use
Scan Screw Lugs to test for Y-Scan signal if the Y-Drive boards are removed.
Y-SUS P212 Connector Diode Mode Testing
Y-SUS Floating Ground (FG 15V) and (FG 5V) Checks
Voltage
Measurements for the Y-SUS Board.
TIP:
These components are on the back of the board. To Test these voltages, remove
the board completely, supply Ground and any 5V supply to M5V fuse FS202.
Y-SUS
16V Generation Check
16V
Test Point
Used in the Y-SUS for Waveform Creation and Leaves the Y-SUS board on P101 pins 1~3 to the Control Board.
Checked at Cathode Side D515.
Standby: 0V Diode Check: 1.32V
Used in the Y-SUS for Waveform Creation and Leaves the Y-SUS board on P101 pins 1~3 to the Control Board.
Checked at Cathode Side D515.
Standby: 0V Diode Check: 1.32V
P101 Y-SUS to Control Board Fuse Information
Y-SUS P113 and P114 Plug Information
Y-SUS P211 Plug Information and Y-SUS P101 to Control P111 Plug
Voltage Check
