Scan Ic(Y Drv B/D : Ic1~10) Damage; Tcp Damage - HP PL4260N Service Manual

3-3. SCAN IC(Y DRV B/D : IC1~10) Damage

(1) In case of SCAN IC poor, one horizontal line may open
at screen.
Test Point: Enlarge after measuring
O
GND ~ Output ICT on Y DRV B/D
Wave format : As shown fig. 4
O
<Fig. 4 When SCAN IC is poor>
(2) Screen may not shown when SCAN IC is damaged by
SCAN IC poor, external electricity or spark.
Test Point : Enlarge after measuring
O
GND ~ Output ICT on Y DRV B/D
Wave format : Output wave format isn't output
O
(You can see the damage for Y DRV B/D's
SCAN IC)
(3) In case of shorting the SCAN IC output by a dust, foreign
substance, it may overlap two horizontal lines on screen.
Test Point : Enlarge after measuring
O
GND ~ Output ICT on Y DRV B/D
Wave format : As shown fig. 5
O
<Fig. 5 When SCAN IC output is short>
7us
60V
<Fig. 6 SCAN IC Normal Output Wave >

3-4. TCP Damage

(1) In case of shorting or opening the IC output of TCP, it may
show one or several vertical lines.
Test Point : Enlarge after measuring
O
Output TP of GND ~ TCP
Wave format : As shown output fig. 7
O
In case of normal wave output, when STB signal is
generated, maintain High output. And when STB signal
is generated again must be fall Low.
But when IC of TCP is poor, STB signal is not generated
Output falls with Low.
<Fig. 7 When IC output of COF is poor>
Remove SR before measuring because the output TP of TCP
is covered with SR. Insulate again with insulating tape after
measuring.