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SCHEMATIC CHANGES AND EQUIPMENT DIFFERENCES



IDENTIFIER DESCRIPTION

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C311, 10 pF, was added. This change eases oscillator adjustment at factory. If this component is not in your unit, do not add It.

CR301, 1N4454, was 1N34A. This change uses a newer, improveel diode. Either diode can be used in this application. When stock is depleted, recommend using lN4454 diodes.

R212, 1 megohm, added. This change reduces first transmitter mixer bias in receive operation. If this component is not in the unit, It does not have to be added.

C219, 100 pF, was 1000 pF. This change improves decoupling between first transmitter mixer and first receiver mixer. If replacing this component, recommend replaeing with 100 pF.

R197, 2200 ohms, replaced L3, 2 mH. This change improves decoupling. If the circuit contains L3, It does not have to be replaced with R197. If L3 requires replacement, recommend replacing with R197.

C238, 0.1 F, was 0.01 F. This change improves decoupling. If replacing this component, recommend replacing with 0.1 F.

R22, 100 ohms, was 56 ohms and R196, 100 ohms, was added. These changes isolate the external vfo from the internal vfo. If Rl96 is not in the unit, it does not have to be added. In this case, R22 should remain at 56 ohms. If replacing these components, recommend replacing with 100 ohms.

R162 is a test select component; 47 ohms to 100 ohms. The value is selected in manufacturing test to provide 1.25 Vac at pin 9 of V2A when EMISSI0N switch is set to LSB (refer to paragraph 4.7 for procedure) and vfo dial setting to 100.

C60, 10 pF, was 20 pF. This change improved decoupling between transmit and receive circuits. If replacing this component, recommend replacing with 10 pF.

CR9, 1N458, added; R93, 1 megohm, was added as 220 kW, then changed to 1 megohm; and R194, 470 kW, was added as 100 kW, then changed to 470 kW. These changes help isolate second receiver mixer from first transmitter mixer. If these components are not in the unit, they do not have to be added. If replacing any of these components, recommend replacing with values shown on schematic.

R145, 82 kW, was 150 kW, 68 kW, or 47 kW on some units. If R145 is 82 kW, C262 (second receiver If amplifier cathode bypass capacitor) should not be in the unit. This change reduces receiver If gain. If replacing R145, recommend replacing with 82 kW). At the same time, check for presence of C262; if C262 is in the unit, remove It. IF C262 fails, recommend deleting it from the unit and replacing R145, If necessary with 82 kW. If the circuit configuration is changed, recheck the receiver gain.

R158 is normally 220 ohms. However, an additional resistor of 56 to 220 ohms may be connected in parallel with the 220-ohm component to give an S-meter reading of S8 to S9 +10 with a receiver input signal of 100 hard microvolts (refer to paragraph 4.7 for procedure).

KWM-2 and KWM-2,A Transceivers. Schematic Diagram
figure 7-l (Sheet A)

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