Table 2-3. Troubleshooting - TM-11-6130-429-400039

TM 11-6130-429-40

Table 2-3. Troubleshooting-Continued

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 4. Voltage Regulator Circuit on A1 PCB (fig. 2-7).

a. Using voltmeter, check for +15 to 17 VDC across C1.

Check Q1, Q2, and associated components. Replace defective component.

CAUTION

Use care when checking voltages and waveforms around the integrated circuits so adjacent leads are

not shorted together. Catastrophic failure may result.

b. Check for + 5 to 7 Vdc at U1-15.

Repair wiring.

c. Check for +5 .2 Vdc between U1-8 (-) and U1-16 (+).

Check components associated with U1-16.

Replace defective components/replace U1.

d. Using voltmeter, check for +2.08 to 2.44 Vdc between U1-8 and U1-1.

Check components associated with U1-1 (and U1-16). Replace defective component/replace U1.

e. Using voltmeter, check for +2.6 to 2.85 Vdc between U1-8 and U1-2.

Check components associated with U 1-2 (and U1-16). Replace defective component/replace U1.

f. Using scope (1V/Div, DC), connect 1:1 probe between U1-7 and C1 (-)). Adjust scope as required to observe display as

Check C3. replace C3 if defective/replace U1.

g. Connect scope probe between U1-3 and C1(-). Adjust scope as required to observe display as shown in figure 2-7.

Check C2, replace C2 if defective/replace U1.

h. Connect scope probe between U1-9 and C1 (-), observe dc level of 1.6 to 3.6 Vdc.

Check components associated with U1-9. Replace defective components/replace U1.

2-13