Service manual

23
7-1. Dynamic Focus
Focus is poor
Is the
waveform of the
DF pin in FBT
correct?
ORION : 300V 150V
1. Check the CRT socket
or connector wire
2. Trouble in FBT or CRT
1. Check the waveform of
the pin 4 of FBT.
2. Check D705
1. Check the 12V DC line.
2. Check Q703, Q704
* Check after adjusting the static focus
finely by VR in FBT
DF
waveform
FVH
FVH FVV
FVV
No
Is the
base voltage of
the Q703 about
12V?
Yes
Yes
Yes
Is the
waveform of
the pin 8 in IC501
correct?
Yes
No
No
Trouble in Q701, Q702
Trouble in IC501 or C523
No
DF
waveform
4.5V
2V
0V
0.8V
Is the
cathode voltage
of the D705
about 700V?