Advertisement
EN 16
5.
LGE PDP 2K5
5.1.6
Mis-discharge Defect
Most of mis-discharge appearance is a problem of Y-DR, Y-
SUS, or Z board.
Check these boards when mis-discharge occurs.
Figure 5-26 Mis-discharge
Checking Order
1. Check Y- and Z-SUS signal cable.
2. Check if Y-DRV IC is defective.
3. Check Y-SUS board voltages (-Vy, Vscw)
4. Check if Y- and/or Z-SUS IPM are defective (see
paragraph "How to Check IPM" below).
5. Replace Control board
How to Check IPM
Forward direction
Measure between:
•
GND (+) and Sus-out (-).
•
Sus-out (+) and Vs (-).
When each two test diode values is over 0.4V => OK.
Reverse direction
Measure between:
•
GND (-) and Sus-out (+).
•
Sus-out (-) and Vs (+).
When each 4 nodes test diode values is infinite => OK
Figure 5-27 IPM check
Service Modes, Error Codes, and Fault Finding
5.2
5.2.1
F_15590_093.eps
070705
F_15590_095.eps
060705
Detailed Module Check PDP42V7*
No Display
The Screen Does Not Display a Picture
1. Check whether on the CTRL board LED (D1, D2, D3, D4,
and D5) is turned "on" or not.
2. Check the power and signal cable of the CTRL board.
3. Check if the X, Y, and Z boards are plugged in correctly.
4. Check the connection of the X, Y, and Z boards to the
CTRL board.
5. Measure the output wave of X, Y, and Z boards with an
oscilloscope (> 200 MHz) and find the trouble board by
comparing the output wave with below figure.
–
Measure point for Y board: Bead B39.
–
Measure point for Z board: Bead B28.
–
Measure point for X board: P3.
6. Check the SCAN (Y side) IC.
7. Check the DATA (X side) TCP IC.
8. Replace the CTRL board.
9. Check if the fuse of Y and/or Z board is open and replace
when open.
10. Check the input voltage (Vcc= 5 V, Va= 65 V, Vs= 187 V).
Figure 5-28 Y and Z board output waveform (1 Frame)
Set_up : 10 5us
Vs(187V)
Vs
Y
Vs(187V)
0V
1 SF
Set_dn : 100us
Vs
Z Z
165V
0V
1 SF
Z square wave form ( non adjustable )
Figure 5-29 Y and Z board output waveform (1 Sub Frame)
Figure 5-30 X board output waveform (1 Frame)
<
?
<
F_15590_005.eps
060605
Approximately 60 V
( non adjustable )
Scan (115V)
Vy (-80V)
Width ( 1.2~1.8 )
( non adjustable )
H_15593_001.eps
120707
<
F_15590_007.eps
060605
Advertisement
