Safety Related Adjustment - Sony GDM-F520 Service Manual

When replacing or repairing the shown below table, the following
operational checks must be performed as a safety precaution against X-rays
emissions from the unit.
HV ADJ
HV Regulator D Board
Circuit Check
HV Protector D Board
Circuit Check
N Board
Beam Current D Board
Protector Circuit
Check
N Board
* Confirm one minute after turning on the power.

SAFETY RELATED ADJUSTMENT

Part Replaced ([)
RV901
Part Replaced (])
C925, IC901, R901, R902, R905,
R924, R925, R926, RV901, T901
(FBT)
• Mounted D Board
C920, C923, D911, D912, R903, R917,
R918, R919, R920, R923, T901 (FBT)
• Mounted D Board
IC1001, RB1001
• Mounted N Board
C930, D917, R921, R932, R933, R935,
T901 (FBT)
• Mounted D Board
IC1001, RB1001
• Mounted N Board
SECTION 2
a) HV Regulator Circuit Check
1) Turn the RV901 slowly, and adjustment so that high voltage is in the
specified range.
[Specification]: 27.00 ± 0.05 kV
2) Check that the voltage of D912 cathode on the D board is 17.0 V or
more.
b) HV Protector Circuit Check
1) Using external DC Power Supply, apply the voltage shown below
between cathode of D912 and GND, and check that the RASTER
disappers.
[Specification]: 19.95 + 0.00/– 0.05 V
c) Beam Current Protector Circuit Check
1) Connect constant current source to a section between T901 (FBT) qa
pin and GND, and check that the RASTER disappers when the
specified current flows to the qa pin.
[Specification]: 2.12 + 0.00/– 0.01 mA
GDM-F520(E) 2-1