Samsung CKG7507L

7 Troubleshooting
7-2 CKG7507L
7-3 Vertical Line on CRT
Does the drive pulse
appear at the emitter of
Q401?
Yes
Replace Q403 or check its
related circuits.
(C416 and T401)
No
WAVEFORMS
43
Check Q411 and D408.
Does the drive output
pulse appear at the Collector
of Q403?
Yes
17
Check IC402 and its application.
No
Does the pulse appear at
Gate of Q411?
Yes
Replace IC301 and check its related
Vertical IC’s application.
Check the –12V Line at power
secondary part. (D615, C620)
Check R303 and R310.
Replace IC401.
7-2 Horizontal Line on CRT or Rainbow Color on the Screen
The first of all you must check
CN301. Does the –12V appear at
Pin 4 of IC301?
Does the pulse appear at Pin 5
of IC301?
Yes
No
No
Yes
Yes
Does the sawteeth wave appear
at the Pin 9 of IC401?
No
WAVEFORMS
10
7
14
15.8 V (Q411, Gate)
CH1 P-P = 15.8 V CH1 RMS = 8.37 V
14
54.8 V (IC301, #5)
CH1 P-P = 54.8 V CH1 RMS = 6.38 V
10
2.80 V (IC401, #9)
CH1 P-P = 2.80 V CH1 RMS = 3.469 V
7
140 V (Q403, Collector)
CH1 P-P = 140 V CH1 RMS = 52.7 V
17
7.12 V (Q401, #Emitter)
CH1 P-P = 7.12 V CH1 RMS = 4.836 V
43