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sears roadtalker 40 am ssb usb

Discussion in 'CB Radio Modifications' started by whistler, Jul 27, 2010.

  1. whistler

    whistler
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    I picked up a Sears "Road Talker 40" at a yard sale for $15 - it works great!

    Just wanted to know if anyone has a link for the tune up instructions. Can't find it on CB Tricks; so I thought I might pick some brains here.

    I'm new here on this forum.
    My name is Tim and my call is 0773 in San Jose CA.
    Thanks!


     

  2. Robb

    Robb
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    Hi Tim - welcome to the forum.
    I talk to you all of time around here in San Jose CA!

    Which model of Road Talker?
    A picture would be nice to see - too.
    Maybe someone also has a clarifier mod for this radio as well?
     
  3. whistler

    whistler
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    here is a picture of the radio maybe this will help (y)
     

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  4. loosecannon

    loosecannon
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    look at the metal tag on the back of the radio and post the numbers you see on it.
    LC
     
  5. whistler

    whistler
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    ok i will do that.
     
  6. whistler

    whistler
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    is this it?
     

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  7. Carl

    Carl
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    model# 934.38270700
    Modulation - Cut D405 or D406
    Am Power - RT602
    SSB Power - RT701

    [​IMG]
    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.

     
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  8. whistler

    whistler
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    thank you carl
     
  9. Carl

    Carl
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    welcome
     
  10. skybolt58

    skybolt58
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    I see this is OLD, But does any one have info on how to adjust the s/rf meter? On this exact same radio?
     
  11. Double R

    Double R
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    i have this radio it look great with a blue swr meter in it , great talking base radio
     
  12. ddbddg1

    ddbddg1
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    I have the same radio too...sadly it needs some parts right now but it was one of the best talking radios i ever had...i am looking for a parts donor for it... you really got a good deal on that im here to tell you....they sell them on fleabay all day for 70.00 to 125.00
     
  13. Onelasttime

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    That is one of the finest modern PLL tuned SSB 40 CH CB radio's ever built. It puts everything Uniden and Dynscan where doing at the time to shame. Take notice to all the shielding inside that radio. Look how much aluminum is inside the radio to heat sink all the transistors. Look at the quality of the mechanical mode select switch inside that unit. Look at the quality of all the capacitors inside. They used a beefy crystal filter 2166 driver and a 1969 final. Every switch and pot on the control face is top notch. The only thing about them I never liked was the din style mic plug. The transformer could be bigger if you wanted to actually get full power out of them on AC power but you can always run it on DC and not have to contend with the AC power limitations.

    They are a pain in the rear to work on because of how tight the inside and the componet density. Normally I am not against modifying a radio but in this case I would recommend against the PLL modification. It is too easy to get a radio that is easier to mod or and export.

    In fact even if you wanted to have a better mic selection I would not modify the front of the radio. I would add a 1/4 inch phono jack on the back or a 4,5,6,8 pin or RJ45 jack on the back out of sight.

    I am not recommending this to the faint of hart or the hamfisted because the front face plate is not for a beginner. If you really wanted to add channels you could prob use somethings like Digi-Max-Light on it. If I remember right the SM5104 PLL use 8 bit binary with n-divder. On and AM only rig I am pretty sure you could get 12m, 11m and some 10m on an SSB unit I am not sure because I have never modified anything with a SM5104 PLL with SSB. Usually when if you are lucky you get about 1/2 as many channels with an SSB radio depending on how it is doing the mixing if the oscillator is internal or external and what if any doubler or tippler crystals are used etc....Example on a uPD858 it has a max potential of 399 channels for AM only but a uPD858 SSB unit is lucky to get 200 channels. Tank circuits always have to be modified to span that much on a factory radio never made to do that.
     
  14. 2RT307

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    I remember seeing these rigs back in the day, and everyone said they were great rigs. I didn't realize it did AC though. Is it a Cybernet chassis?

    73,
    Brett
     
  15. ExitThirteen

    ExitThirteen
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    Negative, it's actually a Hitachi chassis. Pretty unique and not the easiest to work on, or get parts, but with a good power supply they sounded VERY nice on the air. The built-in power supply was a bit on the weak side, needed the pass regulator transistor upgraded to achieve better performance.

    ~Cheers~
     
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