5 Troubleshooting
CF21M*
5-7
5-1-13 V Size or Pos. Variation Failure
IC250 Pin 23 output varies with
different DAC values?
Yes
Check some parts around IC250.
Check bias voltage.
Check and replace IC250 and IC301.
No
5-1-14 High Voltage Failure
Q504 gate driving pulse exist?
The waveform is right?
Check +12 V line.
Check and replace
Q502, Q503, R511, IC501.
Yes
No
Done.
12
Are there some voltages
(350V, 30V, -210V, etc)
at secondary part of FBT?
Check and replace Q504, D508,
D509, D530, D507, D505.
Yes
No
WAVEFORMS
12
Q504, Gate
Summary of Contents for CF21M
Page 7: ...CF21M 6 1 6 Exploded View and Parts List ...
Page 17: ...10 Schematic Diagrams 10 6 CF21M 1 368 V IC601 1 ...
Page 19: ...10 Schematic Diagrams 10 8 CF21M 19 IC103 5 24 15 CRT Socket Red Green Blue 20 R G B Video ...
Page 21: ...10 Schematic Diagrams 10 10 CF21M Memo ...
Page 22: ...Memo 9 Wiring Diagram 9 2 CF21M ...
Page 23: ...Memo 8 Block Diagrams 8 2 CF21M ...
Page 48: ...Memo 7 Electrical Parts List 7 26 CF21M ...
Page 49: ...7 Electrical Parts List CF21M 7 27 Loc No Code No Description Specification Remarks ...