TM 11-6125-240-34
Table 4-1. General Support Troubleshooting for CSV2215-2 and CSV2215-3 -- Continued
Probable cause
Corrective action
Malfunction
c. Check Q5 or Q6 base-emitter and base-collector
C.
Q5 or Q6 open.
junctions with an ohmmeter. Replace Q5 or Q6 if
either junction is open.
d. CR7 Zener open or high Zener voltage.
from anode to cathode for an open circuit. If it
checks good, measure the Zener Voltage, using
any suitable device, either in or out of the circuit,
with 50 microamps reverse current. Replace CR7
if the Zener voltage is greater than 19 volts or if
it checks open as a normal diode.
e. Connect an ohmmeter to the centertap (w/red lead)
terminal of variable resistor R16 and to the high
regulator).
potential (w/orange lead) terminal of same.
Change setting to both ends of trawl. The resis-
tance must read less than 10 ohms at one end
and 10K to 12K at the other end of travel. If not,
remove and replace R16.
With an ohmmeter check CR6 from anode to
f. CR6 defective.
cathode for a short or open. Replace as required.
Measure R7 and R8 resistance with an ohmmeter.
g. R7 or R8 open or high resistance.
Replace either resistor if it measures greater
than 35K ohms.
h. Measure R11 resistance with an ohmmeter. If it
h. R11 shorted or low resistance.
measures less than 13K ohms, replace it.
i. Measure resistance of R12 with an ohmmeter. If it
measures less than 2.5K ohms, remove and
recheck it. If it checks greater than 2.5K out of
the circuit, it is good. C7 then should be replaced
since it will either be shorted or have excessive
leakage.
Remove C5 from circuit and measure the capaci-
a.
a. C5 defective.
Frequency unstable.
tance by any convenient means. The value
should be between 0.8 and 1.2 microfarads.
Replace, if not within tolerance.
Remove C4 from circuit and measure the capaci-
b.
b. C4 defective.
tance by any convenient means. The value
should be between 18 and 26 microfarads.
Replace, if not within tolerance.
c. Measure the resistance of R9 with an ohmmeter.
c. R9 defective.
The resistance should be between 1 K ohms and
2K ohms. Replace, if not within tolerances.
Remove C6 from circuit and measure the capacitance
Voltage unstable.
C6 defective.
by any convenient means. Replace C6 if its value is
not between 0.27 and 0.39 microfarads.
Refer to figure 4-2 for location of parts.
4-6. Troubleshooting Table for 4B93-1-A
b. A pointed probe will be required to puncture the
a. Troubleshoot the 4B93-1-A regulator card assem-
p r o t e c t i v e coating when checking the circuit of the
bly in accordance with table 4-2. Inspect the circuit
regulator card assembly. After repairs are completed,
card assembly and connecting leads before
this coating must be restored in accordance with para-
troubleshooting. Unless a defective part can be located
visually, the sequence of operations in the table should
be followed, since they are listed in order of probability.
Table 4-2. General Support Troubleshooting for 4B93-1-A
Step
Corrective action
Probable cause
No.
Malfunction
a. Set variable resistor R5 for correct fre-
a. Frequency adjustments resistor R5 in-
Frequency out of tolerance.
1
quency.
correctly set.
b. Check CR2, CR3, CR4 and CR5. Replace
b. Zener reference changed
faulty components.
a. Check CR2, CR3, CR4 and CR5. Replace
a. Zener reference changed.
Poor frequency regulation.
2
faulty component.
b. Check all capacitors in frequency sec-
b. Incorrect capacitor valves.
4-5
