Antenna Coupler CU-2229/URC-92 Checkout/Troubleshoot

TM 11-5820-873-34

Table 4-2. Checkout/Troubleshoot the Receiver-Transmitter RT-1277/URC-92--Continued

STEP

ACTION

INDICATION

NEXT STEP

1A4A2U3 is not at fault; 3. If TP3 is below 1.5 V, TP2 should

be below 15 MHz and vice versa. When yes, check divider

circuit; when on, check oscillator circuit.

302

Replace and/or repair VHF Divider CCA 1A4A4.

Use

---

conventional troubleshooting methods for CCA repair. (If off

frequency by approximately 1 MHz but good when 100 KHz

control is on zero--check 1A4A4U4.)

303

Replace and/or repair DC Inverter Assy. 1A6A2.

Use

conventional troubleshooting methods for repair. (If blowing

transistors and/or inverter doesn't work--check 1A6A2K1.)

differently by the procedure. The troubleshooting does

4-6.

Antenna

Coupler

CU-2229/URC-92

not consider incorrect or missing supply voltages to

Checkout/Troubleshoot

subassemblies. Before any replace/repair action is

accomplished on a subassembly, the test technician

The following procedure in Table 4-3 will establish the

should verify all necessary supply voltages at the

operational readiness of CU-2229/URC-92 antenna

subassembly. Incorrect or missing supply voltages

coupler. Successful completion of the checkout portion

should be repaired using conventional troubleshooting

indicates the antenna coupler is operationally ready for

methods. Refer to List of Illustrations for the appropriate

use.

Troubleshooting procedures are designed to

schematics.

function from incorrect indications in the checkout.

Following any repair action, the test technician must

return to step 1 of the checkout unless instructed

Table 4-3. Checkout/Troubleshoot the Antenna Coupler CU-2229/URC-92

STEP

ACTION

INDICATION

NEXT STEP

Remove case from Antenna Coupler CU-2229/ URC-92.

Step 2a

Connect RF and control cables between the Antenna Coupler to

be checked and a known good RT-1277/URC-92 Receiver-

Transmitter. Insure the receiver-transmitter is correctly powered

and grounded.

Set mode switch to AM.

COUPLER STATUS FAULT indicator illuminates.

Yes: step 2b

No: step 8

Disconnect RF cable at the receiver-transmitter. Connect a 50

ohm dummy load to the receiver transmitter.

NOTE

A means of timing, in seconds, is required for this step.

Set mode switch to CPLR TUNE KW. Depress TUNE START.

COUPLER STATUS FAULT indicator goes out.

Yes: step 3a

Begin timing and observe COUPLER STATUS indicators.

COUPLER STATUS TUNING indicator is illuminated

No: step 24

and transmitter keys on. After 35 to 45 seconds,

transmitter unkeys and COUPLER STATUS TUNING

indicator goes out. COUPLER STATUS FAULT

indicator illuminates.

Disconnect dummy load from receiver-transmitter. Reconnect

COUPLET STATUS TUNING indicator illuminates,

Yes: step 3b

rf cable from Antenna Coupler. Connect 50 ohm dummy load to

transmitter keys and both drive motors, 2M1 and 2M2,

No: step 50

the Antenna Coupler antenna post. Connect ground post to

dive.

ground. Set frequency to 1.602 MHz. Depress TUNE START.

Set mode selector to CW.

COUPLER STATUS FAULT indicator is illuminated,

Yes: step 4a

transmitter unkeys and drive motors stop driving.

No: step 90

Set mode switch to CPLR TUNE KW. Depress TUNE START.

NOTE

If the time delay runs out during this test, depress

TUNE START once more. If tuning occurs the

second time the indication is good.

4-22