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SCHEMATIC CHANGES AND EQUIPMENT DIFFERENCES



IDENTIFIER DESCRIPTION

<=9= (cont.)
 

<=9A=
 

<=10=
 
 
 
 

<=10A=
 

<=11=
 
 
 
 

<=11A=
 

R46, 2200 ohlns, was 3300 ohms on some units, If replacing this component, recommend replacing with 2200 ohms.

L22 was changed to a shielded type to reduce bfo leakage, effective C1 72165. When replacing L22 recommend replacing with the shielded type.

R195, 47 ohms, added. this change helps prevent spurious oscillation. If this component is not in the circuit. It does not have to be added.

C55, 180 pF, was 100 pF. This change decreases oscillator feedback if replacing this component, recommend replacing with 180 PF.

EXT VFO POWER connector J17 was changed from Amphenol type to a Collins type. When replacing this connector, recommend replacing with the Collins type.

C47, 0.068 F, has changed value and type. It has changed In value (was 0.047 F) to Increase the VOX time constant. It has changed in type (to a polycarbonate dielectric) to reduce electrical leakage that could result in the VOX relay circuit staying activated. If replacing this component, recommend replacing wlth the 0.068-F polyearbonate dlelectric.

External power connections made to the KWM-2/2A are as follow:

Power Plugs

<=12=
 
 
 
 
 
 
 
 
 
 
 
 
 

<=13=

 

 

 

(Cont)

L2, 10 mH, added; R207, 680 ohms, was added as 470 ohms, then changed to 680 ohms, and C216, 0 02 F, has changed location (previously located between Junction of R18-R141 and chassis) These changes Improve decoupling. If L2 and R207 are not in the unit, they do not have to be added C216 would then be located between junction of R18-R144 and chassis. If replacing any of these components, recommend replacing with values shown on schematic.

R38, 220 ohms, added as 68 ohms, tlhen changed to 220 ohms when R18, 18 kW, was changed from 17 to 18 kW. R38 was added to improve the range of ALC ZERO control R30. R18 was chaeged to increase transmitter If amplifier V4A gain. R38 was changed to maintain proper circuit voltage levels. If R38 is not in the unit, it does not have to be added. If R18 is 47 kW, R38 should be 68 ohms; If R18 Is 18 kW, R38 should be 220 ohms. If replacing R18, recommend replacing wlth 18 kW and at the same time replace R38, If necessary, with 220 ohms.

R98, 27 kW, 16 In some units. this resistor was added to reduce if leakage, but then removed to improve If gain.If this component is in the unit, It need not be removed.

Some early units have mechanical filter FL1 (part number 526-9337-00). Later units have mcchanical filter FL1 (part number 526-9427-000). The two types of mechanical filters are electrically the same but physically different. It is recommended that this component be replaced with same part numbered component. To repace the older mechanical filter (part number 526-9337-00) with the newer one (part number 626-9427-000) bracket having part number 544-9714-002 must be replaced with a bracket having a part number 606-9731-001. Bracket part number 606-9731-001 has a clip to hold the mechanical filter.

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

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