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Sears Roadtalker 40 Base Station Clarifier mod

Alex7590

Member
Dec 17, 2016
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Hello, does anyone know the proper way to unlock the clarifier on the Sears 934.38310700 Base Station. I have the schematic but not sure which wire goes to 8v and ground. I believe the white wire goes to a constant 8 volts and the yellow goes to ground. Could someone out here confirm this?

Thanks
Alex
 

I'm looking at Sam's CB-274. Hopefully they used the same wire colors the day they built your radio. But, if this thing is accurate, the yellow wire gets its power from IC501, which is only active during receive. The white wire is what feeds the voltage to the varactor D702 to change your frequency. The green wire, oddly enough, goes to ground. On TX the 8 volts comes through D710, then R702.

To unlock the clarifier it looks like the yellow wire should be fed by pin2 of IC502, and one end of either D710 or R702 lifted. IC502 should be on in both RX and TX and pumping out a consistent 8 Volts.

Before you start soldering, use your multimeter and check all this for yourself. Sam's is pretty good, but it's no substitute for what's right in front of you in the real world. And I could be wrong, there's always that.

After you're done, do an alignment. The TX, RX, or both voltages may have changed a bit from where they were when being fed by the original components, and that will change your operating frequency.
 
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