TM 11-6125-240-34
Table 4-1. General Support Troubleshooting for CSV2215-2 and CSV2215-3-- Continued
Corrective action
Probable cause
Malfunction
replace Q3. If Q3 is replaced, check CR3 from
anode to cathode for an open or shorted junction.
e.
Measure R3 resistance with an ohmmeter reverse
e. R3 open or high resistance.
meter leads and measure again. If either of the
indications are in excess of 1200 ohms, replace
R3.
Repeat the preceding procedure for Rl, R2 and R4.
f. R1, R2 or R4 open or high.
f.
The greater indication must be less than 8000
ohms for Rl, 15,000 ohms for R2 and 100 ohms
for R4.
Check CR1 with an ohmmeter. Replace if it
g. CR1 open or shorted.
g.
measures either shorted or open.
h.
Check CR9 with an ohmmeter. Replace if it
h. CR9 open.
measures open.
Remove C1 and C2 from the circuit and measure
i.
i.
Cl or C2 defective.
the capacitance with available equipment. The
value should be 0.013 to 0.017 microfarads, and
0.13 to 0.17 microfarads, respectively. Replace
either capacitor that is out of tolerance.
Check Q8 base-emitter and base-collector junctions
a.
a. Q8 open.
No output voltage.
with an ohmmeter, If either junctions checks
open, replace Q8. If Q8 is replaced, check Q7 and
QA per fifth procedure listed for this trouble.
Replace parts as required
Check Q5 and Q6 collector-emitter and collector-
b. Q5 or Q6 shorted.
b.
base junctions with an ohmmeter. If either junc-
tion checks shorted, replace the defective tran-
sistor.
Check CR? for a short from anode to cathode with
c.
c. CR7 shorted.
ohmmeter (use ohmmeter with less than 18 volt
batteries). If junction checks short, replace CR7.
Measure R15 resistance with an ohmmeter.
d.
d. R15 open or high resistance.
Reverse ohmmeter leads and measure again. If
either indication is in excess of 1200 ohms,
replace R15.
e.
Remove Q7 from the circuit board and check base-
e. Q7 open, CR8 open.
emitter and base-collector junctions with an
ohmmeter. If either junction checks open,
replace Q5. If Q5 is replaced, also check CR8
from anode to cathode for open junction.
Check CR7 Zener diode either on or off the circuit
a. CR7 Zener voltage low.
a.
Low output voltage.
board suitable for measuring the Zener voltage.
With reverse current of 50 microamps,
remeasure the Zener voltage. Replace CR7 if the
Zener voltage is less than 17 volts.
Measure the resistance between the center tap
b.
b. R16 open (if connected to regulator).
(w/red lead) and the low potential (w/green lead)
side of R16 variable resistor. This resistance
must be less than 12K ohms; replace R16 if out-
side limit.
Measure R11 and R12 resistance with an ohm-
c. R11 or R12 open or high resistance.
c.
meter. The resistance must be less than 17K and
4K ohms, respectively. Replace parts as required.
d. R7 or R8 shorted or low resistance.
d.
Measure R7 and R8 resistance with an ohmmeter.
Each resistor must measure 30K ohms minimum.
Replace either resistor that is outside limit.
a. Q8 show CR8 open.
Check Q6 collector-emitter and collector-base junc-
a.
High output voltage.
tions with an ohmmeter. If either junction is
shorted, replace Q8 Also, if Q8 is replaced, check
CR8 from anode to cathode for open circuit and
check Q? per following procedure. Replace parts
as required.
b. Q7 shorted.
h.
Check Q7 collector-emitter and collector-base junc-
tions for short circuits. Replace Q7 if either junc-
tion is shorted.
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