GDM-FW9011
HV Regulator
Circuit Check
HV Protector
Circuit Check
Beam Current
Protector Circuit
Check
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.
SECTION 3
SAFETY RELATED ADJUSTMENT
3-1
Part Replaced (
[
)
RV901
HV ADJ
*
Confirm one minute after turning on the power.
a) HV Regulator Circuit Check
1) Enter black crosshatch signal (black on white back-
ground), and check that high voltage is in the speci-
fied range.
[Specification]: 28.50
±
0.10 kV
2) Check that the voltage of D912 cathode on the D
board is 29.0 V or more.
b) HV Protector Circuit Check
1) Enter black crosshatch signal (black on white back-
ground).
2) Apply the specified voltage to the D912 cathode on
the D board, and check that high voltage is 0.1 kV or
less.
[Specification]: 34.00 + 0.00/– 0.05 V
c) Beam Current Protector Circuit Check
(1st Protector): D Board
1) Apply 4.5 V DC to CN504
0
pin on the D board,
and check high voltage value.
2) Connect constant current source to a section between
T902 (FBT)
qa
pin and
qs
pin (GND) on the D board,
and check that high voltage checked in 1) lowers by
1.50 kV or more when the specified current flows to
the
qa
pin.
[Specification]: 2.00 + 0.00/– 0.01 mA
d) Beam Current Protector Circuit Check
(2nd Protector): D Board
1) Connect constant current source to a section between
T902 (FBT)
qa
pin and
qs
pin (GND) on the D board,
and check that the voltage of CN504
0
pin becomes
0 V or less when the specified current flows to the
qa
pin.
[Specification]: 1.63 + 0.00/– 0.01 mA
e) Beam Current Protector Circuit Check
: G Board
1) Apply 264 V AC.
2) Enter about 5 V to CN650
4
pin on the G board, and
check that the output voltage of CN653
2
pin is
about 15 V.
3) Enter about 0
±
0.2 V to CN650
4
pin, and check
that the output voltage of CN653
2
pin becomes 1.0
V or less.
f) Beam Current Protector Circuit Check
: N Board
1) Check that the protector operates, when the voltage
of CN010
qh
pin on the N board is lowered to 0 V or
less (for more than 2 seconds).
Part Replaced (
]
)
D Board IC901, R923, R924,
R929, R943, T902(FBT)
• Mounted D Board
D Board C922, C926, D912,
D915, D921, Q907,
Q908, R921, R922,
R932, R937, R939,
T902(FBT)
• Mounted D Board
D Board C921, C933, D901,
D913, R920, R928,
R930, R931, T902(FBT)
• Mounted D Board
N Board IC001, R031, R032
• Mounted N Board