7 Troubleshooting
7-14
CHA42*7L/5**7L
7-2-12 High Voltage Failure
Is Q508’s drain waveform ok?
Check and replace it.
No
Check and replace AFC input line
from T501 to IC401’s Pin 12. :
D412, D413,
C441, R401.
Yes
Are Q508, D515, L501 ok?
No
Yes
Check and replace it.
Are Q402, D409, D408, D403
and Q410 ok?
No
Yes
Is 56 V on C617?
Refer to 7-2-1 No Power.
No
Yes
Does the PWM duty of IC202’s Pin
16 vary with different H_freq.?
Check and replace IC202,
Q203,
D216.
No
Yes
WAVEFORMS
13
11
Are D503, D505, D519, R508, R506,
R530, Q203, D216 and D415 ok?
Check and replace it.
No
Yes
Does B_Out duty of IC401’s
Pin 28 vary with different
H_frequency and image load
(Full White or No Video)?
Check and replace
IC401,
Q507,
Q509,
T501
and REG_IN line to
IC401’s Pin 15.
No
Yes
Check and replace Q507, Q509,
IC401, T501.
11
CH1 P-P = 5.12 V
CH1 RMS = 4.256 V
12
14.0 V (IC401, #28)
CH1 P-P = 14.0 V
CH1 RMS = 7.34 V
13
136 V (Q508, Drain)
CH1 P-P = 136 V
CH1 RMS = 78.3 V
Symptoms 1: – No Power
– No Raster
– Unstable operation (Fixed FBT B+ voltage with different H_frequency,
Over 31 kHz: whistle sound, Narrow H_Size, Unsynchronized image, 31 kHz: OK)
12
Summary of Contents for CHA4217L
Page 2: ...Samsung Electronics Co Ltd August 1998 Printed in Korea Code No BH68 61127A ...
Page 10: ...Memo 3 Product Specifications 3 4 CHA42 7L 5 7L ...
Page 14: ...5 Disassembly and Reassembly 5 2 CHA42 7L 5 7L Memo ...
Page 62: ...9 Electrical Parts List 9 14 CHA42 7L 5 7L Memo ...