Chapter 5. FUNCTIONING OF TEST PANEL

TM 11-6625-924-14

CHAPTER 5

FUNCTIONING OF TEST PANEL

5-1. General Functioning

to the rotor of synchro transmitter No. 1 and through

a. Because the test panel is made up of switches,

POINTER NO. 1 & 2-ALL OTHER TESTS switch S4

synchros, binding posts, etc., it does not operate on its

(POINTER NO. 1 &2 position) to the rotor of transmit-

own but depends for its operation on circuits and com-

ter B301. Accuracy of the pointer No. 1 reading is

ponents within the indicator. Therefore, functioning of

checked by rotating it with synchro transmitter No. 1

the test panel is described (para 5-2 through 5-13) in

and comparing the two readings which should coincide

terms of the tests it performs on the indicator.

within 1.5 degrees.

Electronic Control Amplifier AM-3209/ASN mounted

5-6. Pointer No. 2 Test, Functioning

internally in the test panel, amplifies signals from the

This test is the same as the pointer No. 1 test except

indicator. Refer to TM 11-6110-211-15 for its function-

that the stator of synchro transmitter No. 1 is con-

ing.

nected to pointer No. 2 through the No. 2 position of

b. Power 115 vat, 400 Hertz is applied to the test

POINTERS switch S-1A and in turn through each of

panel input transformer through the power cable and

the three positions of ADF-VOR-RMI switch S3 to

the ON-OFF switch. A POWER indicator is connected

transmitter B302 which rotates the pointer.

across the primary of the transformer to indicate that

5-7. Heading Dial Test, Functioning

power is applied (ON-OFF switch in the ON position).

The transformer steps down the 115 vac to 26 vac for

In this test, the heading dial of the indicator is rotated

use in the synchro transmitters. The 26 vac is also rec-

through 60-degree increments with synchro transmit-

tified to provide dc voltage for use in various tests of

ter No. 2. The setting of the synchro, and the position of

the indicator.

the heading dial, should coincide within 0.5 degree.

5-2. High Pot. Test

5-8. B306 Calibration Error Test, Function-

ing

In this test, a high voltage from Ohmmeter ZM-21(*)/U

is applied through the HIGH POT binding posts, PIN

In this test, the rotor of B306 is rotated in 60-degree in-

SELECTOR switch, and the HIGH POT position of the

crements by synchro transmitter No. 2 through head-

HIGH POT-NORMAL switch to each pin of the indica-

ing control transmitter B303. The input to the stator of

tor connector in turn. If the ohmmeter indicates

B306 is varied by rotating synchro transmitter No. 1 in

step with synchro transmitter No. 2. If the two synchro

250,000 ohms or greater for each pin, leakage of the in-

dicator is considered normal.

transmitters are within 0.5 degree, as indicated by a

null at the B306 rotor, B306 is within calibration

5-3. Lighting Test, Functioning

limits.

In this test, 5 vdc is applied to the 5 VDC binding posts

5-9. B307 Calibration Error Test, Function-

and then through the lighting circuit of the indicator. If

ing

the AN/USM-223 indicates 1.08 amperes 0.12, the

lighting circuit is functioning normally.

In this test, B307 is rotated by synchro transmitted No.

2 through heading selector transmitted B304, in 60-

5-4. B306 Rotor Turning Check, Function-

degree increments For each setting of the synchro

ing

transmitted No. 2, a null, as indicated by the

In this check, flux valve T-611 is connected to the sta-

ME-30A/U placed across B307 stator terminals (B307-

tor of B306 X-Y-Z binding posts to simulate a normal

B308-B304 switch in B307 position), indicates that

load, and a 740 10 Hertz or is applied to its tuned

B307 is within calibration limits.

rotor through the B306 VTVM binding posts. The rotor

5-10. B308 Calibration Error Test, Func-

of B306 is then rotated through 360 degrees by rotating

tioning

the synchro transmitter No. 1 control (POINTER NO.

l-NO. 2-B306 in the NO. 2 position) to check for bad

This test is the same as the B307 calibration error test

wiper contacts that might cause frequency pulling of

(para 5-9) except that the outputs of B307 are

the 740-Hertz rotor signal.

measured by the ME-30A/U (B307-B308-B304 switch

in B308 position).

5-5. Pointer No. 1 Test, Functioning

5-11. B304 Calibration Error Test, Func-

In this check, the stator of synchro transmitter No. 1 is

tioning

connected to pointer No. 1 through the No. 1 position of

pointers switch S1-A and in turn through each of the

In this test, the rotor of B304 and the set HDG cursor

three positions of ADF-VOR-RMI switch S3 to

on the indicator are rotated, by means of the set HDG

transmitter B301 which rotates the pointer, Twenty-

control, in 60-degree increments. If the output of B304,

six volts is applied directly from the input power source

as measured by the ME-30A/U connected across its

5-1