Federal stock No.
Analyzer, Spectrum TS-723(*)/
(equivalent to be selected).
Power Supply PP-3940/G ----------
Tee Connector UG-274B/U ----------
Test Cables W15, W1, W2,
W3, W22, and W25.
Charger, Battery PP-1451/G --------
Electronic Counter, Digital
Analyzer, Spectrum TS-723(*)/U represents Analyzer, Spectrurn TS-733A/U, TS-723B/U, or TS-732C/U, or TS-723D/U.
Oscilloscope AN/USM-140(*) represents Oscilloscope AN/USM-140A or AN/USM-140B.
Multimeter MS-26(*)/U represents Multimeter ME-26A/U, ME-26B/U, ME-26C/U. or ME-26D/U.
2-4. Use of Troubleshooting Charts
Troubleshooting the SM-442A/GRC is based on the
1. Test set A2 contains transistor circuits. Never
trouble localization and trouble isolation charts given in
connect the 2 types of test equipments which have
TM 11-6625-847-12 and the troubleshooting charts in
outputs directly to transistor circuits; use coupling
capacitors. Some of the modules have input and output
troubleshooting, if trouble within the SM-442A is isolated
coupling capacitors in their circuitry; check the schematic
to a module or assembly, perform or apply the corrective
diagram of the respective modular assembly.
the proper technique in isolating defective parts within a
stage. The troubleshooting charts given in TM 11-6625-
2. Make test equipment connections with care so
847-12 are suitable for isolating SM-442A/GRC
that short circuits will not be caused by exposed test
malfunctions of controls, switches, indicating lamps,
equipment connectors. Tape or use sleeves (spaghetti)
modules, and subassemblies; however, they are not to be
on test prods or clips as necessary to leave as little area
used to locate troubles within a defective module or
exposed as needed to make contact to the circuit under
subassembly. If organizational maintenance has not
isolated a trouble to a control, switch, module, or
subassembly, general support maintenance will start
3. The test set is recommended as a source of
troubleshooting by using the troubleshooting checks in TM
power (para. 2-5) when servicing the transistorized
11-6625-847-12 and performing the corrective actions
modules and subassemblies. Observe the polarity of the
Polarity reversal may damage the
transistors or electrolytic capacitors in the circuit. If a
2-5. Power Supply Requirements
power -source other than the one contained in the test 9 is
used, it must have good voltage regulator and low ac
Testing the various modules and subassemblies of the
ripple. Good regulation is important because the output
SM-442A/GRC requires connection to a power source of
voltage of a power supply that has poor regulation may
+ 20-3 -, and + 27 volt dc, depending on the power
exceed i maximum voltage rating of the transistors the
requirements of the module or subassembly being tested.
module or subassembly being tested.