ST-800/900
Maintenance manual
8
Judge the emitting tube is good or not without power on
11.1.2
、
Receiving tube: pull out the connecting line of the receiving tube, then measure the receiving tube by the
use of digital multimeter with 2MΩ or 20MΩ resistance grade.
Judge the receiving tube is good or not without power on
Y
The positive direction of the emitting tube is
1.0-
1.1KΩ; the negtive direction is infinite
Both of the negative
and positive directions
have
a
certain
resistance value
Both of the negative and
positive directions are
infinite
Positive direction
resistance value
＜
1.0KΩ
Negative direction
resistance value infinite
N
The aging of
the
emitting
The emitting tube
changes value
Disconnection of the
emitting tube
Replace the emitting tube
Parameter
is
normal
Check the emitting tube
operating circuit
Y
The positive direction of the receiving
tube is dozens of KΩ
or hundreds of KΩ; the
negative direction is infinite
Both of the negative and positive
directions
have
a
certain
resistance value
Both of the negative and
positive directions are infinite
N
The receiving tube breakdown
Disconnection of the receiving tube
Replace the receiving tube
Parameter
is
normal
Check the receiving tube
operating circuit
