Samsung DP14LS Service Manual page 36

6-2-15 Invariable Contrast, Brightness Control
Refer to 6-2-18 Key Check.
(Contrast, Brightness)
2
I C check (6-2-13)
Yes
Does IC101's output
(Pins 18, 21 and 23) vary, pressing
15
cont, bright key?
Yes
Does IC103's output
(Pins 1, 2 and 3) vary, pressing
16
cont, bright key?
Yes
Check and replace Q101R, Q101G,
Q101B, Q102R, Q102G, Q102B,
Q103R, Q103G, Q103B.
DP14L*/DP15L*
No
Replace IC101.
No
Replace IC103.
6 Troubleshooting
WAVEFORMS
15 3.16 V (IC101, #21)
CH1 P-P = 3.16 V CH1 RMS = 1.008 V
43.2 V (IC103, #3)
16
CH1 P-P = 43.2 V CH1 RMS = 63.56 V
6-17