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HOLD DOWN OR SAFETY CIRCUIT
INFORMATION
INFORMATION
To monitor the high voltage, the positive DC voltage from the
cathode D512 is applied through R788 and other resistors to
pin 3 of IC475, which is the input terminal of the X-ray Pro-
tection Circuit. The voltage at pin 2 of IC457 is adjusted by
R720 at 5.83 +0.01, -0.02 voltage. Under normal conditions
this voltage is insufficient to activate the X-ray Protection Cir-
cuit.
cathode D512 is applied through R788 and other resistors to
pin 3 of IC475, which is the input terminal of the X-ray Pro-
tection Circuit. The voltage at pin 2 of IC457 is adjusted by
R720 at 5.83 +0.01, -0.02 voltage. Under normal conditions
this voltage is insufficient to activate the X-ray Protection Cir-
cuit.
If the voltage at pin 3 of IC457 increases over the voltage at
pin 2 of IC457 increases and causes the X-ray Protection to
activate. Then it causes the shut down works.
pin 2 of IC457 increases and causes the X-ray Protection to
activate. Then it causes the shut down works.
In the process described above, the voltage at pin 3 of IC457
is compared with the voltage at pin 2 of IC457.
if excessive beam current is drawn, the voltage at oin 3 of
IC457 increases. When the voltage at pin 3 of IC457 over the
voltage at pin 2 of IC457, the voltage at pin 1 of IC457
becomes “high” and feeds into Base of Q401, and the volt-
age at Corrector of Q401 becomes “high” and feeds into pin
38 of micro-controller IC5508 through R5618.
The micro-controller then turns off Q802, causes the AC
power relay RL001 to unlatch and turns off the receiver.
is compared with the voltage at pin 2 of IC457.
if excessive beam current is drawn, the voltage at oin 3 of
IC457 increases. When the voltage at pin 3 of IC457 over the
voltage at pin 2 of IC457, the voltage at pin 1 of IC457
becomes “high” and feeds into Base of Q401, and the volt-
age at Corrector of Q401 becomes “high” and feeds into pin
38 of micro-controller IC5508 through R5618.
The micro-controller then turns off Q802, causes the AC
power relay RL001 to unlatch and turns off the receiver.
Service Instruction: Procedure to apply
silicone to the seal control R720
silicone to the seal control R720
Purpose
To prevent any adjustment on the sealed control after final
adjustment is done at factory. If the sealant are removed
for any reason, the control is damaged at same time.
adjustment is done at factory. If the sealant are removed
for any reason, the control is damaged at same time.
Material
1. Silicone-Type T8C1710201H, manufactured by Shin-Etsu
Chemical Co., Ltd. (Japan)
2. Hard ABS tube-Type TMMX004
Tools
No tool is required.
Procedures
1. Place the hard ABS tube on the designated sealed con-
trol,
trol,
as shown in Figure a.
Figure a.
2. When the tube is gently pressed all the way down and
adhere to the P.C.B., apply the silicon into the hard ABS
tube and form hemisphere like object on the top of tube, a
tube and form hemisphere like object on the top of tube, a
shown in Figure b.
Figure b.
6
1
+
-
X-Ray Detect
38
7
1
2
3
12V
R809
Q802
R810
R5568
IC5508
R5618
R770
C481
R773
R720
R522
R788
R521
D512
FBT T551
R520
C528
R721
12V
EHT
CRT
IC457
AC POWER RELAY
RL001
Comparator Ref.
Comparator out
Comparator in
Silicone
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