5018 (UNIT 2) POWER SUPPLY TEST.

TM 11-5820-918-13

e. Turn on the +35 VDC supply and adjust potentiometer R3 on the card for a

voltage of +28.9 VDC at TP1.

Meter should read +28.2 VDC ( 0.lVDC)

f. Move the voltmeter to terminal E4.

if the batteries are charging properly.

If the voltage at E4 is greater than +28.3 volts, check fuse F2 and switch S1

for continuity or replace battery pack.

h. If voltage at E4 is less than +28.1 volts, allow battery pack to charge for 24

hours, then repeat steps e and f. If E4 voltage is still low, replace battery pack.

i. Turn off +35 VDC supply, disconnect supply and DVM, and momentarily depress

pushbutton switch S1 on the circuit card.

Replace battery box cover and reinsert battery drawer into 1024 front panel.

5-28. 5018 (UNIT 2) POWER SUPPLY TEST.

Remove 5018 top cover and locate connector 2A1J4 at left side of unit (from

front). Refer to figure 2-3. Remove 5018 RF input from the 1024 by disconnecting

the 5018 rear panel connector at J1.

b. Use a needle probe on a DC multimeter and check for a voltage reading of 27

1 VDC with less than 20 mV peak to peak AC ripple at connector terminals J4-A, J4-B,

J4-C, J4-D, and J4-E. If voltages are approximately 7 volts instead of 27, the over

temperature thermostat has activated.

c. Measure DC bias voltages on transistor emitters of RF driver amplifier (2A1A2A2)

and on the four RF power amplifiers (2A1A2A4-A7) with DC voltmeter and verify or

adjust as indicated below:

CAUTION

When making measurements described below, make sure RF input power

is disconnected. Do not short transistor emitter resistors to ground with

meter probe as this may damage the transistors.

Driver Amplifier 2A1A2A2:

0.8 0.2V

Q1-E

2.5 0.3V

Q2-E

1.7 0.2V

Q3-E

107 0.2V

Q4-E

Q5-E thru Q8-E 2.7

0.3V DC

Power Amplifiers 2A1A2A4 through 2A1A2A7

2.8 0.2V DC

Q1-E

Both transistors

Q2-E

(measure across

should be about

equal.

10 ohm 2 watt

emitter resistors).

5-16