Samsung CKB5237L Service Manual page 33

6-4 No Raster (1)
If in a protection case, you must check these case
• Check CN401
• Check Screen VR
• Check VR501
Does secondary voltage appear
at D605, D606, D608, D611 and
D614?
Yes
Does DC 5 V appear at Pin 12 of
IC202?
Yes
Does H-out signal appear at Pin
6
26 of IC302?
Yes
Does signal appear at base
of Q403?
Yes
Does signal appear at collector
of Q403?
Yes
Does flyback signal appear at
14
collector of Q406?
Yes
Does switching pulse appear at
22
base and collector of Q503?
23
Yes
Does signal appear at gate
of Q504 ?
Yes
Check Q504, D508 and FBT.
CKB5237L/7227L
No
Check Power parts.
No
Check protection case.
No
Does DC +5 V, DC +12 V appear
at Pins 29, and 32 of IC302?
Yes
No
Check Q412 and Q414.
No
Check Q403.
No
Check Q406.
No
Check Q503, Q510, Q512 and Q513.
No
Check IC501 and FBT.
6 Troubleshooting
WAVEFORMS
6 8.80 V (IC302, #26)
CH1 P-P = 8.80 V CH1 RMS = 6.176 V
No
Check IC600
and IC603.
Check IC302.
14 1.016 kV (Q406, Collector)
CH1 P-P = 1.016 kV CH1 RMS = 316.0 V
22 5.28 V (Q503, Base)
CH1 P-P = 5.28 V CH1 RMS = 1.290 V
23 848 V (Q503, Collector)
CH1 P-P = 848 V CH1 RMS = 305.2 V
6-3