AV-21F1P
No. 56033
22
■
X-RAY PROTECTION CHECK
Measuring
Item
Test point
Adjustment part
instrument
Check of
Pins 1 and 3
X-RAY
PROTEC-
[X Connector
TION
on MAIN
PWB]
Description
●
Prepare the following resistor.
17.2k
Ω
±
1% 1/4W
1.
Turn on the power and receive any signal.
2.
Connect the resistor between pins 1 and 3 of the X connector
on the Main PW Board.
3.
Make sure that the picture disappears.
4.
Unplug the AC power cord.
5.
Disconnect the resistor from the X connector.
6.
Plug the AC power cord and make sure that the picture ap-
pears normally.
X-Ray Protector Operation:
Normally the voltage at point "A" does not exceed the Zener volt-
age of D562. (The voltage at point "A" will be determined by divid-
ing the voltage from HVT (FBT) by R562 and R563.)
When you connect a resistor of 17.2k
Ω
or less in parallel with
R562, the voltage at point "A" is increased, D562 turns ON, and
the X-ray protection circuit is activated. Once it is activated, you
need to unplug the AC power cord to restore the X-ray protection
circuit.
X
R563
TO HVT
C561
D562
R562
+
D561
1
2
3
MAIN PWB
17.2k
Ω
1% 1/4W
FR561
X-RAY PROTECTOR
A
This Manual: http://www.manuallib.com/file/2595095