TM 11-6625-539-14-4
c. Operate the POLARITY switch to EB posi-
b. Reverse Leakage Test. Make an in-circuit re-
tion.
verse leakage test for the device if IR test values
are given for the device in section IV, appendix D.
d. Adjust ICES ZERO/OHMS ADJ COARSE and
Test as follows:
FINE controls to indicate infinite reading on the
(1) Operate the POLARITY switch to PNP.
OHMS scale of the meter. Short the E-B jacks
(2) Operate the FUNCTION switch to ICO IR
together. Zero the meter using the METER
position.
ZERO control. Remove the short and readjust as
necessary for infinite reading. Repeat the proce-
(3) Operate the RANGE switch to X 10. Check
dure as required until zero and infinity are prop-
for meter zero. If necessary, zero the meter using
erly set.
the METER ZERO control.
(4) Adjust the RANGE switch as required by
the value of the device under test as indicated in
coded remote test jacks. Connect the red lead to
section II of appendix D. Set to:
the collector of the in-circuit transistor, connect
X 0.1 for 0 to 10
the black lead to base, and connect the yellow lead
X 1.0 for 0 to 100 A
to emitter.
X 10 for 0 to 1.0 mA
f. Resistive loading across the emitter-base cir-
(5) Operate the FUNCTION switch to ICES and
cuit will be indicated on the OHMS scale of the
use the ICES ZERO/OHMS ADJ COARSE and
meter.
FINE controls to zero the meter in this setting.
NOTE
(6) Press and hold the It,, toggle switch to the
Resistive loading across any of the three
READ position and adjust the meter to zero, if
available positions shall not exceed 500
necessary, using METER ZERO control. Release
ohms if reliable beta results are to be
the toggle switch so that it returns to the ZERO
read.
position and zero the meter using the ICES ZERO/
OHMS ADJ FINE control.
g. Operate POLARITY switch to CB and read
(7) Connect the test leads to the color-matched
the resistive load across the transistor collector-
remote test jacks. Connect the red lead to the
base circuit.
anode and the black lead to the cathode.
h. Operate the POLARITY switch to E-C and
(8) Use the ICES ZERO/OHMS ADJ COARSE
read the resistive load across the emitter-collector
and FINE controls to zero the meter. This will
circuit.
null the effects of the circuit loading.
i. A scan of the schematic diagram of the equip-
(9) Press and hold the ICES toggle switch to
ment under test will provide an approximation of
READ and check the indication on the meter.
the resistance across each of the circuits. If test
Multiply the reading by the setting of the RANGE
results differ greatly from the schematic diagram,
switch. This is the ICES value. Compare this value
a thorough checkout of the related circuit is re-
with that in section IV of appendix D. Reject the
quired.
diode if leakage is greater than that listed.
(10) Disconnect the test leads from the device
j. Operate POLARITY switch to OFF and dis-
under test. Turn the POLARITY switch to OFF.
connect test leads.
2-15. Ohms Function
2-16. Procedures for Placing Equipment in
Standby Condition
The ohms function of the test set provides a
convenient method for checking out resistive load-
No special procedure is required for placing the
ing of the circuits that parallel the transistor
equipment in standby condition, except that you
circuits. This will alert you if the circuit is such
must turn the POLARITY switch to the OFF
that in-circuit tests are possible, and may help you
position to prevent battery drain. Since no warm-
to isolate faults that appear to be transistor ori-
up of the set is required, it is ready for immediate
ented, but in actuality are defects in the related
use any time.
circuit.
a. Operation the FUNCTION switch to OHMS
2-17. Procedures for Shutdown
position.
To shut down the equipment, make sure the
POLARITY switch is in the OFF position. Discon-
b. Operate the RANGE switch to X 1.0 position.
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