LOCAL OSCILLATOR A1500 ALINEMENT. - TM-11-5820-401-34-30457

TM 11-5820-401-34-3/0967-LP-432-3060

5-15. CRYSTAL REFERENCE SYSTEM (CRS) TEST. (CONT)

14. Connect T-connector to frequency counter.

15. Set AN/URM-103 RF OUTPUT control to 125 KUV.

16. Adjust AN/URM-103 RF TUNING control for 42.00-MHz output. Verify frequency on

frequency counter.

17. Set ME-26(*)/U to 3-vdc scale and turn ZERO ADJ for midscaie reading.

18. Connect ME-26(*)/U positive lead to TP3001 (3) and negative lead to ground.

19. Check reading on ME-26(*)/U. Meter should read zero vdc (midscale), with SIight

fluctuation.

NOTE

If ME-26(*)/U reads greater than + 0.32 vdc or less than -0.32 vdc, the CRS is

defective. See the troubleshooting section.

20. Slowly turn AN/URM-103 RF TUNING control to increase output frequency to 42.25 MHz.

Note change in reading on ME-26(*)/U.

21. Slowly turn AN/URM-103 RF TUNING control to decrease output frequency to 41.75 MHz.

Note change in reading on ME-26(*)/U.

NOTE

In steps 20 and 21, ME-26(*)/U should vary smoothly at least + 0.5 vdc and then at least

-0.5 vdc. If not, the CRS is defective. See the troubleshooting section.

22. Proceed to paragraph 5-16, Local Oscillator A1500 Alinement.

5-16. LOCAL OSCILLATOR A1500 ALINEMENT.

PURPOSE. If the local oscillator is operating at the correct frequency, the CRS will not ouput a dc

error signal. This procedure alines the oscillator by tuning its circuits to bring the CRS error signal as

close to zero as possible. The Crystal Reference System Test (paragraph 5-15) must be done prior to

performing this alinement.

TEST EQUIPMENT AND MATERIALS

Signal Generator AN/URM-103

Matching Unit CN-901/U

Frequency Counter AN/USM-207

T-Connector UG-274/U

Power Supply PP-1104(*)/G

Loudspeaker LS-454/U

Test Cable No. 1

Multimeter ME-26(*)/U

5-93