ADJUSTMENT PROCEDURE-continued - TM-11-5820-670-300237

TM 11-5820-670-30

2-35. RECEIVER SENSITIVITY ADJUSTMENTS. (CONT)

13. Change frequency to 75.00 MHz and repeat step 10, tuning 65.00 and 75.00 MHz coils using

a nonmetallic alinement tool.

14. With frequency at 75.00 MHz, repeat step 10, tuning the 65.00 and 75.00 MHz capacitors

using a small jeweler's screwdriver.

15. If tests are still unsuccessful, substitute boards as necessary and repeat alinement procedures,

or refer radio to higher level of maintenance.

EL1AT246

16. If a distorted signal is observed, perform steps 17 through 23.

17. Attach CG-3376/U from J107 on test set to INPUT of oscilloscope.

18. Connect test set to RT-823/ARC-131 with J117.

19. Use CG-3370/U to connect Signal Generator AN/URM-103 (LO-RF) to test set at J112.

20. Set control unit and signal generator to corresponding frequencies.

21. Set control unit mode switch to T/R.

22. Using screwdriver, unscrew if. amplifier board A4000 and lift up to gain access to two variable

coils on the side.

23. With a nonmetallic alinement tool, adjust the two coils while observing signal on oscillo-

scope. Adjust slowly and observe signal to adjust its symmetry.

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