AN/ARC-5 Handbook
Have a look at the manual AN/ARC-5 Handbook online for free. It’s possible to download the document as PDF or print. UserManuals.tech offer 1 ARC manuals and user’s guides for free. Share the user manual or guide on Facebook, Twitter or Google+.
Figure 4-17. Oscillator Check Points 4--16. FINAL AMPLIFIER. (Follow chart below.) STEP TEST POINT TEST EQUIPMENT CONTROLS NORMAL INDICATION POSSIBLE CAUSES OF ABNORMAL INDICATION 1. Emission switch to CW. Power switch to ON. Set COUPLING control to zero. Set the TS-58 switch to position 5. Press the Microphone button. (See figure 4--19.) TS-58 meter indicates l0 (25 ma final PA plate current.) HIGH CURRENT: Poor tracking, refer to ALIGNMENT section, paragraph 3--5; defective tubes or other circuit components in PA; shorted capacitor C-72. NO CURRENT: Defective relay K- 53; defective PA tubes; no plate or screen voltage on PA tubes. 2. Same as Step 1, except set TS-58 switch to position 2. TS-58 meter indicates 34-38 (170-190 volts PA screen voltage.) HIGH VOLTAGE: Defective PA tubes; defective R-89. LOW VOLTAGE: Insufficient excitation; refer to TROUBLE ISOLATION, OSCILLATOR section, paragraph 4--14; shorted screen by-pass capacitors C-64, C- 75, C-71; open screen resistors R- 90, R-94, R-81 and R-89; open secondary windings on modulation transformer T-58. 3. Same as Step I, advance COUPLING control to 3. Adjust ANT ANT current of over 2.0 amperes. TS-58 reading of 60 to 80 (150 Same as above: if normal indications are obtained in
INDUCTANCE control for maximum PA plate current and maximum ANT current. to 200 ma final PA plate current.) Steps 1 and 2, but not Step 3, relay K- 54 (K-55 also, if used) may be defective. Sliding roller contact on ANT TUNING coil may be dirty, corroded, and not making good electrical contact.
4--17. MODULATOR. (Follow chart below.) 4--18. PRELIMINARY INSTRUCTIONS: Set up equipment as illustrated in Figure 4--19, with the transmitter and associated equipment connected as in PERFORMANCE section. By means of shielded cable, connect from vertical input terminals of scope to indicated TEST POINT. Connect output meter across vertical input terminals of the scope. If Weston model 695 output meter is used, set it to 0 decibel range. (If Daven model OP-182 is used set the power multiplier switch to 1 position and set the impedance multiplier switch Phantom Antenna for maximum antenna current, on CW emission, as described in the PERFORMANCE section, TRANSMITTER TRACKING AND LOADING, paragraph 2-30, Steps 1, 2, and 3. Plug a pair of headphones into the headphone jack on the receiver control box, or receiver rack. A loud audio tone or whistle should be heard during each Step given below. STEP TEST POINT TEST EQUIPMENT CONTROLS NORMAL INDICATION POSSIBLE CAUSES OF ABNORMAL INDICATION 1. Emission switch to VOICE. Ro- tare COUPLING control to zero, key transmitter, and advance COUPLING control clockwise until Phantom Antenna meter reads 1.6 amperes. Set emission switch to TONE and key transmitter. Antenna current should increase from 1.6 to 1.9 amperes, when going from VOICE to TONE emission. Audio sine wave pattern scope output meter should read +2 decibels. (1.5 mw on OP-182.) If no or low output meter reading, tone oscillator is defective. If normal output meter reading, but no increase in an- tenna current, modulator tubes and cir- cuit components are defective. 2. Set emission switch to VOICE. Plug microphone into MIC. jack, J-73, on front of modulator. Set output meter on + 12 db range (power multiplier switch to 100 Antenna current should increase from 1.6 to 1.9 amperes when mike is Whistled into. Output meter should indicate + 14 db (+ 2 db, with 0 db now being + 12 db) on loud sustained whistle. (OP- 182 should read I000 mw). Approximate audio sine wave pattern on scope. Defective modulator tubes and circuit components. defective C-29/ARC- 5 control box. Defective receptacles on modulator. Defective microphone circuit. Improper or no voltages on modulator tubes. Defective modulation transformer T-58.
on OP-182). Press microphone button and whistle loud, sustained tone of constant pitch into micro phone. Measure all voltages and make continuity measurements. 3. Set emission switch to TONE. Key transmitter. Antenna current should rise to 1.9 amperes. Output meter should read + 14 db (+ 2 db, with 0 db being + 12 db). (OP-182 meter should read 700 milliwatts.) Same as above. Replace modulator tubes with known good ones. Check for shorted capacitors and open resistors. Check continuity from modulator to transmitter. Figure 4-18. Final Amplifier Check Diagram