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Sears Roadtalker 40 SSB

S

Solosoft

Member
Aug 19, 2009
2
0
11
38
Sudbury,Ontario,Canada
www.solosoft.org
Hey guys, this is my first post to your forum and hopefully not my last. I recently got into the radio game in the last few months. I started off with a crappy antenna and a Realistic TRC-484. I got the manuals for that radio and a SWR/Wattage/Mod Meter and tuned that thing up. Wanting to get out further, I went to a yard sale and picked up this Sears Roadtalker 40 SSB Radio. From what I see it's a "Vintage" Radio and seems to have some positive reviews on alot of the CB websites. I have a few questions on it tho and im unable to find the service module. I found the pods to turn up AM and my Mod.

I got AM sounding sweet. The Radio pushes a 10w Dead Key with about a 15 swing. (I think my SWR meter is a little out tho). During talking the radio dims a little bit but the other end hearing me has NO complaints about the quality of my transmission.

This is the fun part, SSB on the radio I think was previously tuned and does not sound right. When I talk into the radio it sounds like im over modulated. I thought that was the issue but when I calibrated it it looks like im PEAKING the radio at high 80's which is not great mod but definitely not over modulated. Im starting to think the poor radio is way overdriven and I am looking for the POD numbers to turn down my SSB a little bit so the radio doesn't dim so much. According to my Power meter im pushing almost 30w on SSB (again the power meter is from the 70's too so im assuming it's lieing). My SWR is 1.1 on the meter and 1.1ish on the radio.

The question I have is where do I get the service manual for this radio. I will put links of the pictures since ive not been able to find a working model number. Here is all the information I have from the Radio. What im looking for is an idea where to start.

1. What's the most mod/power I should push outa this thing on AM without harming it.
2. What's the most mod/power I should push outa this thing on SSB without harming it/starving it
3. Manual ??? Which Pods handle my SSB output I want to turn it down a little bit. People can hear me well but as soon as it trys to push out that extra little bit it sounds like im clipping. The front display lights almost completely dim on a whistle.

Thanks !!

Front

http://solosoft.org:81/gallery/v/Radio/Sears/IMG_0025_1_.jpg.html

Back

http://solosoft.org:81/gallery/v/Radio/Sears/IMG_0027_1_.jpg.html

If me opening the radio and taking a very high resolution picture would help in ANY way for sure I will do it.

Thanks guys ... I just don't want to break this old radio, and it looks like someone else played with it before.

I did a little more research and found this information.

Sears 663.38100050: <VR1-S Meter, VR2-Sq Range, VR4-Carrier Balance, VR4-AMC, VR6-ALC
VR7-RF Meter, VR8-Final Bias, VR9-Driver Bias, VR10-AM Power>
TX tune-up: SSB: L15, L40, L39, L38, L28

So ... what I understand from this VR1 pod is for my meter up in the front ? This RX/TX right ? How would you tune this is there a special way
VR2 Sq Range - Sounds like a Squelch range ???
VR4 Carrier Balance - What's this exactly for ?? Im assuming it's the power of my carrier on AM
VR4 AMC - No Idea lol
VR6 ALC - Sounds expensive lol ... no idea tho ...
VR7-RF Meter - I think this might be the meter up in the front
VR8 - Final - im assuming this is for my final power ???
VR9 - Driver Bias - ???
VR10 - AM Power - Makes sense right ?

SSB: L15, L40, L39, L38, L28

Im assuming those pods are for the SSB which is what im looking for, but there is no description of what they exactly do ???

Thanks guys ... if I find more information i'll keep posting it as I go ... Sorry guys im not the greatest at this but am definitely learning as I go. Any help would be great.
 
Last edited:

Solosoft said:
Hey guys, this is my first post to your forum and hopefully not my last. I recently got into the radio game in the last few months. I started off with a crappy antenna and a Realistic TRC-484. I got the manuals for that radio and a SWR/Wattage/Mod Meter and tuned that thing up. Wanting to get out further, I went to a yard sale and picked up this Sears Roadtalker 40 SSB Radio. From what I see it's a "Vintage" Radio and seems to have some positive reviews on alot of the CB websites. I have a few questions on it tho and im unable to find the service module. I found the pods to turn up AM and my Mod.

I got AM sounding sweet. The Radio pushes a 10w Dead Key with about a 15 swing. (I think my SWR meter is a little out tho). During talking the radio dims a little bit but the other end hearing me has NO complaints about the quality of my transmission.

This is the fun part, SSB on the radio I think was previously tuned and does not sound right. When I talk into the radio it sounds like im over modulated. I thought that was the issue but when I calibrated it it looks like im PEAKING the radio at high 80's which is not great mod but definitely not over modulated. Im starting to think the poor radio is way overdriven and I am looking for the POD numbers to turn down my SSB a little bit so the radio doesn't dim so much. According to my Power meter im pushing almost 30w on SSB (again the power meter is from the 70's too so im assuming it's lieing). My SWR is 1.1 on the meter and 1.1ish on the radio.

The question I have is where do I get the service manual for this radio. I will put links of the pictures since ive not been able to find a working model number. Here is all the information I have from the Radio. What im looking for is an idea where to start.

1. What's the most mod/power I should push outa this thing on AM without harming it.
2. What's the most mod/power I should push outa this thing on SSB without harming it/starving it
3. Manual ??? Which Pods handle my SSB output I want to turn it down a little bit. People can hear me well but as soon as it trys to push out that extra little bit it sounds like im clipping. The front display lights almost completely dim on a whistle.

Thanks !!

Front

http://solosoft.org:81/gallery/v/Radio/Sears/IMG_0025_1_.jpg.html

Back

http://solosoft.org:81/gallery/v/Radio/Sears/IMG_0027_1_.jpg.html

If me opening the radio and taking a very high resolution picture would help in ANY way for sure I will do it.

Thanks guys ... I just don't want to break this old radio, and it looks like someone else played with it before.

I did a little more research and found this information.

Sears 663.38100050: <VR1-S Meter, VR2-Sq Range, VR4-Carrier Balance, VR4-AMC, VR6-ALC
VR7-RF Meter, VR8-Final Bias, VR9-Driver Bias, VR10-AM Power>
TX tune-up: SSB: L15, L40, L39, L38, L28

So ... what I understand from this VR1 pod is for my meter up in the front ? This RX/TX right ? How would you tune this is there a special way
VR2 Sq Range - Sounds like a Squelch range ???
VR4 Carrier Balance - What's this exactly for ?? Im assuming it's the power of my carrier on AM
VR4 AMC - No Idea lol
VR6 ALC - Sounds expensive lol ... no idea tho ...
VR7-RF Meter - I think this might be the meter up in the front
VR8 - Final - im assuming this is for my final power ???
VR9 - Driver Bias - ???
VR10 - AM Power - Makes sense right ?

SSB: L15, L40, L39, L38, L28

Im assuming those pods are for the SSB which is what im looking for, but there is no description of what they exactly do ???

Thanks guys ... if I find more information i'll keep posting it as I go ... Sorry guys im not the greatest at this but am definitely learning as I go. Any help would be great.
Click to expand...

First of all - I am NO EXPERT! But I do play around with radios and have fixed and adjusted a few with success - with no failures.

10 watts dead key is too high and may cause premature failure of the output transistors. No more than 4-5 watts would be best (VR10 from what you've described). So, I would turn down the AM carrier. This may also affect the problem you are having with SSB. Radios need to have balanced adjustments to function and to keep functioning properly.

Don't mess with the final bias or the driver bias settings - unless they are wrong. Generally speaking, the driver bias is about 30 ma and the final bias is about 50 ma measured from test points on the board. Changing these values to anything other than what is required will gain NOTHING except problems. This can also lead to premature final/driver failure if set incorrectly. You need a multimeter and a service manual to do that correctly. I haven't found one online; but it may exist and may be available somewhere. If you already have the manual; then I would follow it to the letter.

The carrier balance is used to adjust the amount of carrier power on SSB. There should be no carrier power that can be read on a meter when keying the mic on either USB or LSB. That is the only time it needs to be adjusted - to turn that pot so that no power can be measured on either USB/LSB.

Speaking of meters, if you are going to mess with radio adjustments - you need something more accurate than what youi described as using. Astatic/Paradynamics makes an inexpensive and fairly accurate meter that will work for your purposes. If you can get one used for ~$40 - you have done OK. Don't expect accuracy with what you are using; but for the purpose of measuring average power for the AM carrier - it should work OK.

Finally, the AMC/ALC adjustments will affect the modulation of TX/RX on SSB. Might be the problem area - but check the radio after you have turned down the AM carrier to 4-5 watts first. That may have been the problem - so check it after you re-set the AM deadkey carrier for 4-5 watts! You really need to find a copy of the service manual for this radio and follow it to get all the adjustments right.
 
Last edited:
ok, after blowing up the image of the back of the radio, it looks like your sears radio is the same as the cobra 146GTL, and the uniden PC122.

many radios are the same on the inside and are put in different manufacturers cases.

here is the service manual for the 146GTL.

http://www.cbtricks.com/radios/cobra/146gtl/graphics/cobra_146gtl_sm.pdf

here is a drawing of the layout of the main PC board for the PC122:

http://www.cbtricks.com/radios/uniden/pc_122/graphics/uniden_pc122_main_pcb.pdf
if your radio looks like this on the inside, then this is the info you want.

in looking at it, the VR numbers seem to line up with what you have posted here so far, although i think whoever provided those VR's had a few typos, but looking at the diagram in the service manual that shows where each VR is located should tell you if the info is the correct info for your radio or not.

now, for what the VR's, or POTS (short for potentiometers, AKA Variable Resistors) do:

VR1-this is your S-meter control. it sets the "receive meter" at the correct level. dont mess with it.
VR2-this is your squelch range. it sets the level at which the squelch "breaks". dont mess with it.
VR3-this is your transmit frequency control. it sets the frequency you transmit on. only mess with it if you have a frequency counter.
VR4-this is your carrier balance. on SSB there is no carrier or "deadkey". meaning the radio only puts out power when you talk. this adjustment makes sure there is no power coming out of the radio unless you talk. to set it correctly, set your meter on "power" or "watts", turn the mic gain all the way down, key the mic, and adjust this pot for MINIMUM power out. when set correctly, the meter should not move when you key the mic.
VR5-this is your AMC (automatic modulation control). this is the one you adjust for more modulation. most people just turn it all the way up and then use the external mic gain control to adjust mic gain.
VR6-this is your ALC, or SSB power control. set it for about 12-15 watts on your wattmeter while saying "ahhhh" into the mic.
VR7-this is your RF meter control. it sets the "transmit meter" on the radio to read correctly. it has nothing to do with how much power you are actually putting out, it is just a meter adjustment.
VR8-this is your final bias control. the service manual will tell you where to set it, but unless you already messed with it, or you see its turned all the way one direction; dont mess with it.
VR9-this is your driver bias control. same goes for this one.
VR10-this is your AM power control. it sets the deadkey where you want it. set it for 4 to 5 watts. no more.

good luck, feel free to ask any questions that come up, and always ask them BEFORE you make the adjustment.
LC
 
Last edited:
Dont use it like that. .fixed device is better to use. I used some devices as you. Driving and using the cb is getting too hard by this way. But if u mount it u ll taste better. Nice rig anyway..
 
Thanks guys !!, with the information you got me I took out the multimeter and balanced those inputs from the little metal block thingy on the back. (Ok so I don't know the exact name and got 25mw -> 50mw respectively. The 25mw one was frickin hard to set lol I hickuped and it went up +-30mW but I got that all tuned. Using a properly setup rig I did it the old fashioned way and listened to the warble on the feedback and tuned the pods nicely. I got ~ 8w dead key on AM and ~ 12-14w PEP which seems to be about right on this radio. The SSB is doing ~ 20 peak (whistle) and more like 17-18 on an "AAAUUUUDDDIIOOO" which is a little more realstic with "speaking".

Thanks so much for an idea where to go with this. I really just needed a little boost to get an idea where to go. I think it sounds really nice now and I was able to shoot about 30-40km "How the crow flys" hittin at about 3 bars on a 2970DX on AM and 5 bars on LSB. I think that's more then enough for me lol and really if I wanted to sneak some extra power instead of blowing the finals on that great radio a linear amplifier (which of course for "technical purposes"would not be used on my CB rig ;) would handle that just fine.

I'll try shootin for DX tonite if there is any and giver a good test run. Thanks guys i'll try to stick around the board and help out as much as I can.


Solosoft

ps, the rig is running mobile. There was a 2A fuse in it (I never checked the uniden connector it comes with). Upgrading it to a 5A quick blow fuse fixed some of the dimming. It dims a little more "gracefull" now.
 
Sears Roadtalker 40 am

These are very good radios! I collect vintage radio's of all kinds. I have the black face base. Don't mess around, its having a tech do the work. I am looking for a Sears SSB base in perfect condition.I found another am base and bought that with an unusual Sears roadtalker base microphone
 
I have the SSB base that looks like a recording studio console. It works nice and has good ears to boot..
 
Solosoft said:
Thanks guys !!, with the information you got me I took out the multimeter and balanced those inputs from the little metal block thingy on the back. (Ok so I don't know the exact name and got 25mw -> 50mw respectively. The 25mw one was frickin hard to set lol I hickuped and it went up +-30mW but I got that all tuned. Using a properly setup rig I did it the old fashioned way and listened to the warble on the feedback and tuned the pods nicely. I got ~ 8w dead key on AM and ~ 12-14w PEP which seems to be about right on this radio. The SSB is doing ~ 20 peak (whistle) and more like 17-18 on an "AAAUUUUDDDIIOOO" which is a little more realstic with "speaking".

Thanks so much for an idea where to go with this. I really just needed a little boost to get an idea where to go. I think it sounds really nice now and I was able to shoot about 30-40km "How the crow flys" hittin at about 3 bars on a 2970DX on AM and 5 bars on LSB. I think that's more then enough for me lol and really if I wanted to sneak some extra power instead of blowing the finals on that great radio a linear amplifier (which of course for "technical purposes"would not be used on my CB rig ;) would handle that just fine.

I'll try shootin for DX tonite if there is any and giver a good test run. Thanks guys i'll try to stick around the board and help out as much as I can.


Solosoft

ps, the rig is running mobile. There was a 2A fuse in it (I never checked the uniden connector it comes with). Upgrading it to a 5A quick blow fuse fixed some of the dimming. It dims a little more "gracefull" now.
Click to expand...
I have what you're looking for. Sears AC power supply. Converts Sears DC CB radios
Solosoft said:
Thanks guys !!, with the information you got me I took out the multimeter and balanced those inputs from the little metal block thingy on the back. (Ok so I don't know the exact name and got 25mw -> 50mw respectively. The 25mw one was frickin hard to set lol I hickuped and it went up +-30mW but I got that all tuned. Using a properly setup rig I did it the old fashioned way and listened to the warble on the feedback and tuned the pods nicely. I got ~ 8w dead key on AM and ~ 12-14w PEP which seems to be about right on this radio. The SSB is doing ~ 20 peak (whistle) and more like 17-18 on an "AAAUUUUDDDIIOOO" which is a little more realstic with "speaking".

Thanks so much for an idea where to go with this. I really just needed a little boost to get an idea where to go. I think it sounds really nice now and I was able to shoot about 30-40km "How the crow flys" hittin at about 3 bars on a 2970DX on AM and 5 bars on LSB. I think that's more then enough for me lol and really if I wanted to sneak some extra power instead of blowing the finals on that great radio a linear amplifier (which of course for "technical purposes"would not be used on my CB rig ;) would handle that just fine.

I'll try shootin for DX tonite if there is any and giver a good test run. Thanks guys i'll try to stick around the board and help out as much as I can.


Solosoft

ps, the rig is running mobile. There was a 2A fuse in it (I never checked the uniden connector it comes with). Upgrading it to a 5A quick blow fuse fixed some of the dimming. It dims a little more "gracefull" now.
Click to expand...
I have what you're looking for, still sealed in original package, never opened, never used15405431957833375042132585753153.jpg 15405432452912468720866276448163.jpg 15405433443626714371426960579507.jpg
 
Well how many times have you listed it on ebay? I seen it several times along with a sears roadtalker ssb
 

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