Sears Road Talker 40

[a2phil]

I must be a glutton for punishment. First the Cobra 139 XLR, now I just bought a Sears Road Talker 40. In my defense, I noticed a 3 position switch on the bottom at the garage sale, which upon further investigation, it doesn't seem to do anything on the extra positions but cut off the sound. AM doesn't work, and only LSB works on sideband (no problem for me-I usually talk on LSB) The meter is broken, so I used my own power meter, and it went from about 2 watts to 0. The "fine tune" (clarifier?) seem to affect both TX and RX and is REALLY touchy (from Alfred Hitchcock to the Munchkins on helium in 1 notch!!) Is there a Photofact for it, or any schematics online?

 

[hhrj]

Check Secret CB here: Secret CB

 

[RadioDaze]

Check Secret CB here: Secret CB

Wow - fun site! Brings back memories!

 

[ducksoupe]

Thanks I can use the info

 

[Dawn]

If you're dead on usb/am it might be the loop crystal as it's shared in both modes on the early Hitachi SSB roadtalkers and Pennys units. Look for a choke added in the clarifier circuit. That was commonly added to provide a huge slide between channels.

Which roadtalker do you have? The hitachi's were the slope front with a built-in AC power supply and digital display and the cheaper one that only had a 40 channel dial. Only other one was the base that looked like a top loading tape deck which contained the same chassis as the dial unit. All later Roadtalkers were Uniden chassis. Only docs outside of Sears which I've never seen are the SAMS Photofacts 246 (slopeface) and 254 for the dial one. They quit making them about the same time Sears went Uniden. Penny's models were the same inside but different mic connector and cosmetics.

These are extremely heavily built radios and probably the best 40 channel chassis ever made if you have the Hitachi ones above. They are so tight that mods beyond the 40 channels don't work out to well.

 

[giboni]

Sears Road Talker SSB AM Base Looks Like a Casset Deck

Recent posts !

Just picked up one at the local CB Hack Shop $35.

Needs a thorough cleaning.

Not mint exterior. But it works ! Talked skip from my car on 38LSB. Good reports on AM. Using an inverter.

& Firestick 8 foot 3/4 wave whip.

Plastic amplified base Sears Microphone.

Weighs a Ton. I like this Radio. It replaced my ARF 2001.

Figure a Recap of the larger eloctrolytics first.

Now it is a bit noisy. Perhaps I can improve that once I get the Sams.

On U-tube. A guy has one with upper and lowers. Plus the slide 15kc.

Their was an Expo Kit for this radio Y Kit.

No ANL Just NB.

A Hitachi ? chassis. Hmm This is a keaper like my CP2000,Tram 201A,BrM4A,Trc457 etc.

It was stated here JC Penny chassis same ?

Looking to listen in on uppers and lowers, Slide to A channels.

Need the information. For the Mods !

Thanks in advance for your time.

73s John

 

[LoyalServant]

I would stay away from the "expo kits" that are nothing more than a set of crystals on a switch.
You mention using sideband and those crystals on a wire from my testing tend to be unstable and drift around a lot.

The guys that came up with those mods don't realize you can't stuff a crystal on the end of an 8 inch wire and expect it to have any stability.

 

[giboni]

Hi,

Thank you for taking the time to respond. Wire adds capacitance to Crystals.

Had a feeling they were discontinued for a reason.

As of this post. Still have not taken it out of the Car.

Work tomorrow. Sat & Sunday.

D104 Mic rebuild today.

Compressor Board and Shure element for an acquaintance.

According to the author of this Web Page below. The PCB Guts in my Deluxe Version is the same as the

Slant face Sears Road Talker SSB AM 40 Base Mobile. The Slant face interests me also.

The Deluxe probably uses a Modulation Transformer. Find out later today !

Classic Base and Mobile CB Radios of the 1970s & 1980s | Radio Geek Heaven

Well I bought the Switch on Ebay. This old Webpage in an Internet Archive Shows this Mod.

It sounds similar to a Forum Post in an Amateur Forum for conversion to 10 Meters. That conversion involves swapping one or more I believe "Loop Crystals".
-----------------------------------------------------------------------------------------------------------------------------------------------------------

SEARS ROADTALKER BASE/MOBILE (Double Pole= 2 Pole)

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 posistion/ double pole rotary swicth in the radio.then run wires (the red lines) from the switch posistions 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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I might have to get the Radio that this Modification is for LOL. If the guts are the same. Then the Rotary switch ought to work.

Probably other switches could be used. RadioShack $3.44 shipped. I have wire LOL ! 3KC Slide not worth it for me.

10KC is worth it.

Sams Photofact CB Series 264. Or expensive download from the Sams site. Will ask on Forums if someone has one.

Plenty of room to add a frequency counter. If I can figure out where to wire it in. I think this Radio works as

good as my CP2000 & Trc457. Have the Parts. Will get to the CP2000 soon.

Would like to have Lower Channels also if possible ! Any Information appreciated !

73s Best John

73s Best John