TM  11-5820-890-20-2 2-43 2.2. TROUBLESHOOTING FLOWCHARTS. Continued Chart 9 NO SIDETONE HEARD AT COMMANDER'S C 2298 WITH MONITOR SWITCH IN THE C POSITION. (Sheet 1 of 3) NOTE: Circuit disturbing is used to induce noise into the system. To circuit disturb, set up the multimeter as an ohmmeter. Use the 200 range. Connect the ground probe to pin A and touch the other probe to the indicated pin. Then, quickly lift the probe. Repeat as needed and listen for the clicking sound in the handset. Only the 200 range has an adequate voltage to cause the clicking sound. V U T S R P N M L K J H F E D C B A C 2298 J801, J804 V U T S R P N M L K J H F E D C B A AM 1780 J505, J506, J507 NOTE: Set up multimeter as an AC multimeter. Use lowest range. Connect meter probe between signal line or a test point and chassis ground. Key the handset and whistle into the mic look at the meter and note any change in the AC voltage. The change indicates the presence of the talk signal. The reading will be less than 1 volt. 1 SH 2 1.   SET MONITOR IN C POSITION. 2.   CIRCUIT DISTURB PIN J AT COMMANDER'S C 2298 J801/J804. NO YES CLICKING SOUND HEARD IN HS ? REPLACE COMMANDER'S C 2298. NO YES AC VOLTAGE CHANGES ? 1.   OBSERVE CHANGE IN AC VOLTAGE AT COMMANDER'S C 2298 J801 OR J804, PIN V TO PIN A (GND) (SEE NOTE). 2.   PRESS PTT AND WHISTLE SHARPLY INTO HS. REPLACE COMMANDER'S C 2298. 1.   OBSERVE CHANGE IN AC VOLTAGE AT AM 1780 J505, J506, OR J507, PIN K TO PIN A (GND) (SEE NOTE). 2.   PRESS PTT AND WHISTLE SHARPLY INTO HS. START