One Or Several Horizontal Lines On The Screen; Checking For Component Damage; Low Brightness Of Displayed Picture; Ipm Normal Output - Philips PDP42V7 series Service Manual

EN 18 5. LGE PDP
Figure 5-44 Screen display "Vertical lines"

One or Several Horizontal Lines on the Screen

1. It may be caused by:
– Open or short on SCAN FPC attached panel.
– Defect on SCAN IC attached panel.
2. Replace Y DRV board.
Figure 5-45 Screen display "Horizontal lines"

Low Brightness of Displayed Picture

1. In this case, Z board operation is not correct.
2. Check the power cord of Z board.
3. Check the connector of Z board and CTRL board.
4. Replace the CTRL board or Z board.
Partially Other Colour on Full White Screen or Partially
Discharge on Full Black Screen.
1. Check the declination of Y board set-up and set-down
wave.
2. Measure each output wave with oscilloscope (> 200 MHz)
and compare the data with below figure data. Adjust the Y
board Set_up (A) and Set_down (B) declination by
changing VR1 and VR2 as written on the adjustment label.
– Measuring Point of Y board: B39
Vs
- Vy = - 85 + 1V
Figure 5-46 Y output voltage waveform
No Specified Brightness at Specified Colour
1. Check the connector of CTRL board input signal.
2. Replace the CTRL board.
Service Modes, Error Codes, and Fault Finding
It may show several vert.
lines in a quarter or other
division part of screen
including left case
F_15590_021.eps
040705
It may show several horizontal
lines including left case
F_15590_022.eps
040705
A:10 + 2 µs (Vr1)
Vset_up (=Vs) = 187 ± 1V
B: Vset_down= 100 + 2 µs (Vr2)
(Vr4)
F_15590_023.eps
040705
5.2.3

Checking for Component Damage

Y IPM (IC 15) or Z IPM (IC 2)
When the internal Sustain_IGBT or ER_FET of Y IPM (IC15) or
Z IPM (IC2) is damaged, VS fuse is open and there will be no
picture.
• Test Point: B32-GND (Y board), B28-GND (Z board).
• Wave format: B32 (Y board) or B28 (Z board) has no output
wave.
• Measure position: Sustain section, B32 wave of Y board
and B28 wave of Z board (full white pattern).
Y IPM Y IPM
Z IPM Z IPM
Figure 5-47 IPM normal output
Pass_Top FET (Y board: HS2)
When the Pass_Top FET is damaged, electric discharge of the
entire screen is generated.
• Test Point: GND-B32 (Y board)
• Wave format: When the Set_dn does not descend until -Vy.
Figure 5-48 Pass-Top FET defective
FET Assy (Y board: HS1)
When Set_Up FET is damaged, there will be no picture.
1. Test Point: GND-B32 (Y board)
– Wave format: Set_up waveform is not generated.
2. When Set_Down FET is damaged, electric discharge of
entire screen is generated.
– Test Point: GND-B32 (Y board)
– Wave format: Set_down waveform is not generated.
– Measure position: Reset wave of B32 (Y board) (full
white pattern)
F_15590_024.eps
060605
F_15590_025.eps
040705