7 Troubleshooting
CHA42*7L/5**7L
7-11
7-2-6 Invariable H_Size
Does the PWM duty of IC202’s Pin
18 vary, pressing H_Size button?
Check and replace
Q409.
Yes
Is paravola waveform on
IC401’s Pin 24?
Replace IC401.
Replace IC202.
No
Is Q409 OK?
No
No
No
Yes
Are Q410 and D408 OK?
Replace it.
No
Yes
Check and replace Q408, Q409, L402.
WAVEFORMS
8
8
1.12 V (IC401, #24)
CH1 P-P = 1.12 V
CH1 RMS = 3.094 V
Does PWM duty of IC202’s
Pin 22 vary with different timings?
(Low freq. : narrow duty
High freq. : wide duty)
Check and replace IC202 and some
parts around it.
Check if R444 and R434 are right
as CRT differential items?
Adjust horizontal minium size with
softjig. (Refer to 6-2-1)
No
Does the FBT B+ voltage on T501’s
Pin 2 vary with different timings?
Refer to 7-2-12 High Voltage Failure.
Yes
No
Yes
7-2-7 Abnormal H_Size
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 ...