Samsung CF21M Service Manual page 57

5 Troubleshooting
5-1-15 ABL Failure
Input full white pattern to monitor.
IC102 Pin12 (19": IC101, Pin15)
input exists and
varies with different patterns?
No
Check CN102, Q101, Q102, ZD101.
T501 Pin 8 Voltage exists?
Yes
IC103 Pin 16 output exists and
varies with different patterns?
Yes
Check and replace IC102 and CRT
5-1-16 Focus Failure
IC250 Pin 11 and 32
13
output are right?
Yes
Some parts around Q551,
Q552, Q553 and Q540 are right?
Yes
Some parts around T502 are right?
14
Yes
Does the voltage of Q541
collector change as the FH function
is changed on the OSD menu?
Yes
Check the connection between FBT
Pin 13, CRT Socket PCB.
5-8
Yes
Check and replace IC102 (19":IC101) .
No
Check and replace T501.
No
Check and replace IC103.
No
Check and replace IC261.
No
Replace failed part.
No
Replace failed part.
No
Check Q541 and others components.
WAVEFORMS
2.20 V (IC250, #11, 32)
13
CH1 P-P = 2.20 V CH1 RMS = 2.776 V
580 V (T501, #1)
14
CH1 P-P = 580 V CH1 RMS = 278.2 V
CF21M*