Teletype 43K001/AAA, Repair Manual

Page: 26 / 82

525,2-12
B. TROUBLESHOOTING (Contd)
2. 50K122 UNITIZED KEYBOARD TROUBLESHOOTING (Contd)
410101 CIRCUIT CARD COMPONENT LAYOUT
•• •• ea •• ••
EJE:JEJ��
�o{UJP
CJ CJ c=J CJ
c:::::J � c:::J CJ c:::J C4 $
c=J �
c;J Q �
HLB1
� EJ EJ E:=J EJ EJ E:J � � � EJ
� �
�c:::Jc:=Jc::Jc::=Jc::=;]c::::J�c:;]c::=Jc::;]c::=Jc::::J�CJ
L:J � L:::J LJ LJ � L:J � LJ �· r::J �
�
CJ
c::=J C] c=J c::::J c=J CJ � C] c:::=J c:::=] CJ
c::J
EJ ����EJEJ����� � �
[=::J CJ c=J CJ C] � c:=;J CJ c:::J c:::::J c=J CJ Cd C]
COMPONENT IDENTIFICATION AND LEAD DESIGNATION
CRl
40
Cathode
A
Anode
21
SEMICONDUCTOR IN CIRCUIT STATIC FORWARD RESISTANCE
COMPONENT
CR1
STATIC CIRCUIT RESISTANCE (See Note)
RESISTANCE
30 ohms
CONNECTOR TERMINAL
P107-3 (+12
V)
P107 -2 ( -12
V)
P107-8 (+5
V)
REFERENCE POINT
P107-4 (logic card)
P107-4 (logic card)
P107-4 (logic card)
RESISTANCE
LO HI
Infinity
Infinity
1.5K ohms 6.5K ohms
2K ohms 8.5K ohms
Note: Take resistance reading, reverse meter leads and take second resistance reading.