4011 (UNIT 3) POWER SUPPLY TEST

TM 11-5820-918-13

NOTE

Adjust the 2.8 volt bias by screwdriver adjust potentiometer R3 on bias

regulator subassembly card mounted above each power amplifier card.

If bias cannot be set or if Q1 and Q2 biases differ by more than .25 VDC,

RF power amplifier is defective and should be replaced.

d. Replace covers and cables when finished.

5-29. 4011 (UNIT 3) POWER SUPPLY TEST

CAUTION

Disconnect 5018 power (3J4) to insure that there is no high power

RF present.

a. Remove 4011 top cover. Remove eight screws securing chassis plate (4011- 1001)

and remove chassis plate, disconnecting cables restricting chassis plate if module is

to be removed.

b. Locate the following test points on module 3A2A2 (figure 5-8) and use a multi-

meter to check the voltages specified. Apply power to 4011.

(1) At test point +5A measure +5 0.25 VDC

(2) At test point +6B measure +6 0.25 VDC

(3) At test point +26V measure +26 3 VDC

(4) At test point -250V measure -250 25 VDC

(5) At test point -270V measure -270 30 VDC

(6) AC ripple should be less than 10 mV peak-to-peak on regulated supplies and

less than 10% of nominal DC amplitude on unregulated supplies.

NOTE

In test 3, 4, and 5 above, unregulated supplies are measured. Measure-

ments will vary directly as a function of the input AC line voltage.

Remove power from the 4011.

d. Replace chassis plate (4011-1001) removed in step a.

e. Replace cover removed in step a and replace 4011 in rack. Insure interconnect-

ing cables are properly installed.

5-30. HARMONICS/SPURIOUS RESPONSE TEST. This test measures the harmonics

and spurious response (spurs) of the TCS-4B transmitter. The test is performed

in two parts. An RF Power test (paragraph 5-22) should be performed prior to this

test.