Channel 9 mod question for a newbie

[Klint]

First of all I want to say hey , I’ve just joined up. I have a Vietnam made cobra 29 Ltd classic. Fixing to put in a cap and resistor mod and talk back with the resistor across the ext speaker and pa . I want to hook up the talk back to the channel 9 switch. it appears there are more than two wires on the switch. When I disconnect them , do I need to do anything with the wires or just tape em up and put em away. Also my board says the jp36 jumper is jv6 .. what’s up with that ? I bought the radio new in 2011. Ive done a fair amount of research online and haven’t seen anyone call the jumper a jv6. I’ve also noticed that the components are a set up a little different on my board compared to some of the others that I’ve seen. Anyway this looks like a very interesting forum and glad to be here. Thanks for adding me.... KW

 

[loosecannon]

Kilint,
your answer to this is very important.
we have been getting many new members here asking questions that are easily googled.
can you please prove to us that you're not a bot or a troll?
please excuse these questions if they don't apply.
LC

 

[LeapFrog]

Welcome to the forum Klint!

When you remove or repurpose a channel 9 switch you need to make sure that any and all connections made by the switch in the "normal" position are still going to be made after you remove the switch.

If you find three wires, five wires (or more) it really doesn't matter, you still need to recreate the connections made while the switch was in the "normal" position.
The (now) unused wires can be trimmed and secured with heat shrink tubing and plastic cable ties, or simply removed from the pcb if you desire.

P.S.
I don't recommend the cap/resistor mod, it can (and usually does) create a lot of distortion.

Using just a resistor will get the carrier down, and usually doesn't ruin the AMC function.
At times lowering the ferrite slug in L14 will be enough for some.
You won't have the same "Peak Power", but the signal will be cleaner than when using a capacitor to "bypass" the resistor during modulation.

Disclaimer:
The information included in this post is for educational purposes only and is not intended to be a substitute for adjustment or repair by a licensed technician. Because of unique individual needs, the reader should consult his or her local regulations to determine the appropriateness of the use of this information for his or her intended application.
I assume no responsibility for any misuse of the information provided.


Best Regards
-LeapFrog in the SandPile

 

[Shadetree Mechanic]

Welcome! I also have a 29 LTD Classic that is bone stock. I use it as a station monitor with headphones for my base station. I would like to widen the receive audio some day soon.

 

[Klint]

Welcome to the forum Klint!

When you remove or repurpose a channel 9 switch you need to make sure that any and all connections made by the switch in the "normal" position are still going to be made after you remove the switch.

If you find three wires, five wires (or more) it really doesn't matter, you still need to recreate the connections made while the switch was in the "normal" position.
The (now) unused wires can be trimmed and secured with heat shrink tubing and plastic cable ties, or simply removed from the pcb if you desire.

P.S.
I don't recommend the cap/resistor mod, it can (and usually does) create a lot of distortion.

Using just a resistor will get the carrier down, and usually doesn't ruin the AMC function.
At times lowering the ferrite slug in L14 will be enough for some.
You won't have the same "Peak Power", but the signal will be cleaner than when using a capacitor to "bypass" the resistor during modulation.

Disclaimer:
The information included in this post is for educational purposes only and is not intended to be a substitute for adjustment or repair by a licensed technician. Because of unique individual needs, the reader should consult his or her local regulations to determine the appropriateness of the use of this information for his or her intended application.
I assume no responsibility for any misuse of the information provided.


Best Regards
-LeapFrog in the SandPile

 

[Klint]

Thanks Leapfrog for your valuable input, I may not do the cap mod then. I'm new at this and really am interested in cb mods , but sounds like I need to cool my heels ..Lol

 

[357magnum]

Welcome Klint ! Enjoy the forum ! Lot's of Educated people here . To back Lc up he's right we've been inundated with Pc Pest's lately .73 & God Bless , Leo

 

[Riverman]

Kilint,
your answer to this is very important.
we have been getting many new members here asking questions that are easily googled.
can you please prove to us that you're not a bot or a troll?
please excuse these questions if they don't apply.
LC

Hope this doesn't become our standard reply to new members.
I was however able to pull enough individual letters from it to spell Welcome.

 

[Handy Andy]

First of all I want to say hey , I’ve just joined up. I have a Vietnam made cobra 29 Ltd classic. Fixing to put in a cap and resistor mod and talk back with the resistor across the ext speaker and pa . I want to hook up the talk back to the channel 9 switch. it appears there are more than two wires on the switch. When I disconnect them , do I need to do anything with the wires or just tape em up and put em away. Also my board says the jp36 jumper is jv6 .. what’s up with that ? I bought the radio new in 2011. Ive done a fair amount of research online and haven’t seen anyone call the jumper a jv6. I’ve also noticed that the components are a set up a little different on my board compared to some of the others that I’ve seen. Anyway this looks like a very interesting forum and glad to be here. Thanks for adding me.... KW

First Welcome!

But...

Here's where I stop...

{QUOTE] I’ve also noticed that the components are a set up a little different on my board compared to some of the others that I’ve seen. Anyway this looks like a very interesting forum and glad to be here. Thanks for adding me.... KW[/QUOTE]

Ok, do you have a board number? If you did your research - then you would also see a KEPC ID near the center of the board...Vietnam, Philippines' - Malaysia - no different - all are identified by this ID.

Because your JP36 mod is the same across all boards that use the Cobra 29 KEPC - else you may have something else...

And as you gain experience with this board, you'll also notice too, that no matter what - this board seems to be quite popular and you're now just discovering it - do a search here on these forum boards in this site and you'll find a lot of mods.

Now, in regards to your "Channel 9" That switch may also have a secondary function too - so that means it's a two position switch. with more than one "pole" used to not only tell the PLL "I want Channel 9" - it's got to display it too - so if you haven't already done so - do some more research and find out what wires "short together" when that switch is in the NORMAL position - and wire accordingly. Pull those wire off the switch and solder them to make the NORMAL setting permanent - and then remove the other wires and trim them off so you don't have to worry about shorting or make them live - in error.

You'll find that not all switches are the same in appearance - but electrically they function the same.

IF you're complaining about jv6 printed where jp36 should be - that may be a silkscreen issue or something more serious. IF you are not sure - I highly recommend you either post a pic of what you're up against, so we can decipher it for you, or you really should take it to someone who can.

 

[Klint]

First Welcome!

But...

Here's where I stop...

{QUOTE] I’ve also noticed that the components are a set up a little different on my board compared to some of the others that I’ve seen. Anyway this looks like a very interesting forum and glad to be here. Thanks for adding me.... KW

Ok, do you have a board number? If you did your research - then you would also see a KEPC ID near the center of the board...Vietnam, Philippines' - Malaysia - no different - all are identified by this ID.

Because your JP36 mod is the same across all boards that use the Cobra 29 KEPC - else you may have something else...

And as you gain experience with this board, you'll also notice too, that no matter what - this board seems to be quite popular and you're now just discovering it - do a search here on these forum boards in this site and you'll find a lot of mods.

Now, in regards to your "Channel 9" That switch may also have a secondary function too - so that means it's a two position switch. with more than one "pole" used to not only tell the PLL "I want Channel 9" - it's got to display it too - so if you haven't already done so - do some more research and find out what wires "short together" when that switch is in the NORMAL position - and wire accordingly. Pull those wire off the switch and solder them to make the NORMAL setting permanent - and then remove the other wires and trim them off so you don't have to worry about shorting or make them live - in error.

You'll find that not all switches are the same in appearance - but electrically they function the same.

IF you're complaining about jv6 printed where jp36 should be - that may be a silkscreen issue or something more serious. IF you are not sure - I highly recommend you either post a pic of what you're up against, so we can decipher it for you, or you really should take it to someone who can.[/QUOTE]
Thank you for your welcomed information !!! I think ole Leapfrog has about talked me out of doing the cap and resistor mod. But yes I will take my meter and find out what wires have continuity on the normal side of my switch and put them back together when I get ready to put talk back through it. I like my talk back because I have echo, but I will be turning it off when set because of a humm noise when I key up.

 

[Klint]

I appreciate all of you guys help !! There is a ton of knowledge here I see.

 

[Klint]

If you will pull the picture up you can see where jv6 is where jp36 is supposed to be. That is the same jumper, correct ?

 

[Klint]

Leapfrog I’m not going to do that cap and resistor mod, but was wondering what was up with my board components being numbered and labeled different than most others I’ve seen. By the way just followed your instructions on the selector switch and all is well. I did however turn that vr4 pot out to 100%. That should help with modulation from what I’ve researched.

 

[sonoma]

it is the newest version of the cobra 29 radio. here is the board that is in your radio from Cobra. your serial number should start with a U.

http://downloads.cobra.com/CB/Models/29-SERIES/NewVersion/

 

[Klint]

it is the newest version of the cobra 29 radio. here is the board that is in your radio from Cobra. your serial number should start with a U.

http://downloads.cobra.com/CB/Models/29-SERIES/NewVersion/

it is the newest version of the cobra 29 radio. here is the board that is in your radio from Cobra. your serial number should start with a U.

http://downloads.cobra.com/CB/Models/29-SERIES/NewVersion/