COMPONENT MAINTENANCE MANUAL
IN 1502H RADAR INDICATOR
TM109102
3-2
May/01
(1) Do not use multimeters with sensitivities less than 5000 ohms-per-volt. Use either a
20,000 ohms-per-volt multimeter or a vacuum tube voltmeter.
(2) Do not use test equipment with transformerless power supplies unless an isolation
transformer is used in the a-c power line.
(3) Some test equipment is designed with a line filter across the a-c input. This could
result in accidently applying 55 volts a-c to the semiconductor device. To eliminate this
possibility, always connect a ground wire from the test equipment chassis to the
indicator chassis prior to making any other connections.
B. Capacitor Checking
When checking tantalum capacitors, care should be taken to ensure that the maximum
d-c working voltage, as marked on the capacitor, is not exceeded and that the polarity
markings on the capacitor are observed when applying voltage. Disregarding polarity
markings or exceeding the d-c working voltage may permanently damage the capacitor.
C. Transistor Testing and Base Connections
Tables 3-1 and 3-2 provide typical testing data for PNP and NPN transistors. Table 3-3
lists the transistors used in the indicator. Column 2 references Figure 3-9, which shows
the base arrangement view of the transistor. Transistors having in-line leads must have
leads formed to the standard three pin socket configuration.
NOTE:
The information in tables 3-1 and 3-2 is not applicable for triacs, Darlington
transistors, FETs or the VMOS transistors listed in table 3-3.
PNP Transistor Testing Procedure
Table 3-1 (Sheet 1 of 2)
CHECK
NO.
OHMMETER CONNECTIONS
RANGE
RELATIVE RESISTANCE
BASE
COLLECTOR
EMITTER
1
-
+
RX100 or
RX1000
Low (1000 ohms or less)
2
+
-
RX10,000
High (100,000 ohms or more)
3
-
+
RX10,000
High (100,000 ohms or more)
4
+
-
RX10,000
High (100,000 ohms or more)
5
-
+
RX100 or
RX1000
Low (1000 ohms or less)
6
+
-
RX10,000
High (100,000 ohms or more)
The document reference is online, please check the correspondence between the online documentation and the printed version.
