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SEARS ROADTALKER 934.38270700 BASE/MOBILE

A place to ask questions about base setups.

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goatboy
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SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by goatboy » Tuesday, 14 September 2010, 10:16 AM

Looking for a pdf. schematic for the SEARS ROADTALKER 934.38270700 BASE/MOBILE
have to tune it and get it to modulate better any tips and tricks to tune and adjust this raio would be helpful


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Nagant
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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by Nagant » Tuesday, 14 September 2010, 15:33 PM

Welcome to the forum.

I didn't find a schematic online nor do I have one but I did find some of the info you're looking for in this post on another forum:
model# 934.38270700
Modulation - Cut D405 or D406
Am Power - RT602
SSB Power - RT701

1)Open the radio and you will find a metal case around the pll chip.unsolder this. 2)Cut the trace around pin 9 and 8 . 4)Solder a 4.7k resistor from pin 8 to ground. 5)Install a 6 position/ double pole rotary switch in the radio.then run wires (the red lines) from the switch position's to the locations on the pc board. 6)Solder a 1n914 diode from pin 1 to pin 4 on the switch. 6)Solder a wire from pins 2A to 3A to 4A to 5A.

Adjust t302, the VCO,so that the radio will TX/RX on all the extra channels. HINT:USE A PLASTIC TUNING TOOL TO MAKE THIS ADJUSTMENT OR YOU WILL BREAK THE COIL!!

POSITION 1

Channel 1 to 40 is 26.485 to 26.925

POSITION 2

All the regular CB channels

POSITION 3

Channel 12 to 27 is 27.425 to 27.595

POSITION 4

Channel 1 to 40 is 27.605 to 28.045

POSITION 5 AND 6 will give regular CB Channels

CLARIFIER MODIFICATIONS

1)Find the green wire coming off the FINE TUNING control.Follow the wire to the pc board where it connects and unsolder it.
2)Find the RED wire behind the meter display and solder it to that location(there is 8VDC there)
3)Find the BLACK wire from the FINE TUNING control and unsolder it from the PCB.
4)Solder this wire to PC GROUND .
5)Find the PURPLE wire from the FINE TUNING control and unsolder that from the PC board.
6)Solder this wire to the point on the PC board where R303 and the cathode,the end with the band around it! , of D301.

This mod will give you about 3khz up/down off the "channel".
If you move the clarifier and the radio "drops out" you will need to JUMP d301 and put the purple wire back to where it was.

I have no idea if it's accurate or not.

Your model is in Sams CB Photofact 246. That will have a full schematic as well as alignment.
Worm on AM or 262 on SSB.


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My YouTube CB Radio Channel http://www.youtube.com/user/262NagantRa ... e=mhee#p/u



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goatboy
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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by goatboy » Thursday, 16 September 2010, 17:05 PM

Found more info from sams
AM recieve tune:
L101
T101
T102
T103
T201
T202
T151
T152
SSB Receive tune:
L101
T101
T131
T132
T134
AM Power
RT602
SSB Power
RT701
AM BIAS
RT702
SSB BIAS
RT703

Hope this helps others mine is off freq and need to retune TX/RC

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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by skybolt58 » Tuesday, 07 June 2011, 3:42 AM

would anyone know what pots is for the meter adjustments

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DuckSoupe
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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by DuckSoupe » Monday, 19 November 2012, 16:58 PM

Could I ask what the sears roadtracker ssb mobiles are going for ?


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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by mjc8bal » Thursday, 17 January 2013, 10:50 AM

I just picked one up on ebay for $30 all works good

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giboni
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Re: SEARS ROADTALKER 934.38270700 BASE/MOBILE

Post by giboni » Tuesday, 03 February 2015, 16:19 PM

mjc8bal wrote:I just picked one up on ebay for $30 all works good
I have two plus the premium base.

These Tanks are so underated. Do not cut anything as far as Modulation. Any power Mic will push you to 100% PLUS. Start cutting. You will have issues on Side Band.

I use iether a Turner + 3 on SSB. A Turner Super Side Kick on AM. In the Mobile. An Amplified Shure Noise Cancelling Mic.

I will post in a few weeks maybe months? Sooo many Radios So little time LOL.

A Shotky diode mod and possibly an IF transistor replacement. Tooo bad 7.8mhz Monolithics are no where to be found LOL. But I have chewed up 138xlr with one.

As soon as I get my copy of the Sams will start tinkering. The NB needs improvement. Very underated radio. A sleeper.. Perhaps can get it to the level of my Trc457,458,139Xlr858 washington oh & CP 2000. Currently knocking myself out on a 8719 Washington. Worth it. Has a Digi-scan.

Lot of them & cheap. Sugestion. Just recap the power Supply. This is usually the major problems with these 35+ year old Radios in my experience. Out of the box with a Power Mic.

These radios ARE LOUD ! Receive much better than you would expect. No worse than modern CBs as far as ajacent channel. Sensitivity might be superior to most moden CBs.

Best 73s John


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