TM 11-6125-240-34
Table 4-2. General Support Troublehooting for 4B93-1-A -- continued
Corrective action
Malfunction
Probable cause
tion. Replace faulty components.
3
Low frequency.
Shorted transistors
Check Q4, Q5, Q6 and associated compo-
nents. Replace faulty components.
4
High frequency.
Open transistors
Check Q4, Q5, Q6 and associated compo-
nents. Replace faulty components.
a. Voltage adjustment resistor R2 incor-
5
Ac output voltage out of tolerance.
a. Set variable resistor R2 for correct
rectly set.
voltage.
b. Check CR2, CR3, CR4 and CR5. Replace
b. Zener reference changed.
if faulty.
Excessive modulation of ac output
6
Faulty feedback capacitor C4.
Check C4, Replace faulty component.
voltage.
7
Poor voltage regulation.
a Check C5, Replace faulty component.
a. Faulty input capacitor C5.
b. Faulty reference.
b. Check CR2, CR3, CR4 and CR5. Replace
faulty components.
High output voltage.
8
Shorted transistor.
Check Q7, Q8, Q9,Q11 and associated com-
ponents. Replace faulty components.
Low output voltage.
9
Open transistors.
Check Q7, Q8, Q9 and Q1l. Replace faulty
components.
4-6
