Cobra 29 vr5
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This guide to troubleshooting CB radios and issues will help you find and correct some of the most common problems that plague CB operators.
When people contact us regarding issues, one of the first questions we will ask you is, "Have your tuned your antenna? If your antenna is not tuned, it can cause all sorts of problems! Every CB antenna needs to be tuned to optimize your CB system and ensure that you won't potentially damage your radio. Each section below lists a problem and the potential solutions for it. A link to more information is provided when available. This guide assumes you are using a stock, unmodified radio with a standard CB antenna.
As always, if you can't find what you need here, you can contact us for more help. Make sure the power cord connections are attached correctly. If your radio has a power plug, make sure it is seated well.
Make sure the CB radio's fuse is not blown and that it is seated correctly. Also check the in-line fuse for the CB radio's power cord- if it is burned out, your radio will not power on. Make sure the power is switched on. You should hear a 'click' as you turn it clockwise, indicating the radio's power is on. If your CB radio is not connected directly to the battery, make sure the fuse panel or extension wire it is connected to has a good connection to the battery.
When you turn the channel selector knob, the channel does not change. The channel may show 9, 19 or W and a number.Cobra has really shot themselves in the foot with this new radio, why you ask?
Their Sideband radios such as thegtl and were superb, they were stable and a radio you could be proud of. The first thing that happened to Cobra was that Uniden wanted to raise the price on there PC boards, Cobra did not like this so they got some other company to make there boards cheeper!
Of course this is all history, they fixed that problem. I had a customer send me a NW ST for peaking and tuning for better receive and transmit. So before doing anything else, I hooked it up to my antenna to get some radio checks, well, AM was OK, nothing to write hone about but clear and clean. So I really got concerned!
After checking the oscilator frequencies I find that they change when I modulate! What the Hell! I placed a volt meter on several test points and found that the voltage to the oscillators is changing with modulation! So I start looking for the reason for this and ran into the cause right away. To my knowledge it could be inproved with some additional filtering and RF bypassing.
Cobra HH34 Basic handheld with charging jack and lighter plug. This is a typical example of mis-information, the resistor changes listed below will not produce more power, they will make the radio sound crappie.
Change R76 3. Change R43 10 Ohm to a 2.
Change R 1 Ohm to a. Replace stock final with a 2SC transistor. Re-tune coils L10,L9,L8 for maximum forward Power. Modification: Change stock final to a 2SC Change C71 to a 33uf 16volt polarized electrolytic capacitor. Two, Install a k ohm pot between these two points. The smaller the value, the more the receive is boosted.
Big, Loud, Cobra 29 LTD Radios
Look for the collector of TR, you should read about 4. If you find that this voltage is not present, check on the opposite side of R for 6. Most likely this voltage will not be present; if this is the case, C18 has shorted and needs to be replaced. This is a uf, 10V electrolytic capacitor beside L Transmit Audio normal. The newer units may have corrected this problem. Output level uV.
Set Squelch Maximum. Adjust VR-3 so that squelch just breaks.Crossbones If the driver final is a 2SC, change it to a 2SC Change R to a 0.
Change R58 to a 2. Replace D8 with 2 1N diodes. Change C71 to a 33uf 25v. Do not cut D This will cause over modulation. Solder a uf or larger 25v. Cap with 50 to ohm 1 watt resistor. The lower the resistor value, the higher dead key will be. Recieve gain VR Signal meter VR Squelch VR AMC VR Antenna warning light L This is only on the newer models. Locate pin 14 of the PLL. Install a 22kk ohm resistor between these two points. The smaller the value, the more the recieve is boosted.Log in or Sign up.
Find Trucking Jobs. May 23, 1. This will be somewhat of a long post, but worth reading The info contained herein will save you some money. Ohhhh Yesss it Will They call me Texas Trash on the road I know some of you may know me If you want your Cobra 29 LTD to be a loud booming talker you don't have to pay some cb hacker to "fix ya up". Swing Mods are snake oil Don't pay to have this done Any kind of mod D11 etc, etc. If you really want your radios audio loud and proud you can do it yourself.
It is real easy. Just open that badboy up on the speaker side and find VR VR4 is the AMC pot It controls your audio output Once you find VR Take a plastic screwdriver get a cheap set at Radio ShackAdditionally it can be dangerous and may expose you to electrical shock, injury, or death. CB radios can easily be damaged when tampered with by an untrained individual. This website assumes no responsibility and can not be held liable for the activities or actions of anyone visiting this page.
For many people a CB radio is a mysterious box that allows them to rag chew everyday with their friends. They have no idea how the radio works other than they know how to turn it on, adjust the volume, push the key, and talk. The first thing to know is that whenever you work on a CB radio you should have the proper tools and a static free environment.
A static charge can build up very easily especially in places with dry air. The two things you can do to avoid problems is to buy a set of Alignment tools often called TV repair tools which usually consist of plastic pieces which vary from flathead to hex heads.
For more information on what modulation is or how it effects your CB click here. First what you will want to do is disconnect the power to your radio. How can you tell which side is the component side? The speakers are attached directly to the bottom cover with screws and then have two small wires that run to your PC board. Now you can see the guts and components of your radio. But how do you determine where the modulation potentiometer is when there are so many similar parts on the board?
Well the truth is, there is no easy way, but luckily there were people before you who figured it out and the information is readily available on the internet for you to look up. Most modulation potentiometers inside CB radios look something like this —. Turning it one way will reduce modulation and turning it the other way will increase modulation. Radios and their components vary greatly so often the only way to discover which direction increases modulation is trial and error.
Remember that having work done on your radio is always best done by a professional, but if you feel like trying your hand at certain things the only way to learn is to try. This website is purely for entertainment purposes. Any and all articles, reviews, products, pictures, writings or any other material published on this website are written and are to be used for entertainment purposely only.
All opinions, articles and written statements on this website are opinion.Log in or Sign up.
Turned up 2 pots on my 1993 Cobra 29 LTD Classic
Find Trucking Jobs. Aug 20, 1. Am I correct?
Would like to add talkback and echo. Yes, let employers and TruckersReport text me with new opportunities, job alerts and other career information to the number I provided. There is no charge for this service, but standard message and data rates may apply. Aug 21, 2. RatAug 21, Aug 21, 3. Well you know Channel Jumper, if you don't have echo on your radio, you're not cool.
Just ask some truck drivers. Turbo-TAug 21, Aug 21, 4. I have the echo and talkback turned off in my radios.
I think most that have to have echo and talkback just like to hear themselves talk, it makes them feel important and they think they're trucks go faster with it. BTShepp Thanks this. Aug 22, 5. I know you did not deserve to be berated for wanting to add talkback to your radio or in general even being so stupid as to run a CBby a bunch of ham operators most of whom have never even driven an 18 wheeler.
Hopefully you will not take this poor treatment of your desire to run a CB radio in a truck on the CB section of a truck driving website by a group representing ham radio as an example of all those who do have a ham license. I have no idea why this site is the most poorly moderated board on the internet but there it is. Thread after thread, post after post everywhere on this forum the same thing goes on by mostly the same group of people. Every time a person innocently asks for advice the thread is hijacked to drive the topic in the same direction, namely: 1- ham is better than CB 2- you are a fool, a child, trailer trash, an ignorant moron for not knowing how much better ham is than CB 3- almost no one will try to help answer your question 4- run a repeater, use 2 or 10 meters, surely the loading dock will hear you, surely you will be warned by other drivers on the road about hazards or conditions up ahead if you will only throw away your CB and go ham 5- use your cell phone surely all other drivers have your number 6- I could go on but what is the point If this is how ham operators set a shining example to others of what a great hobby it is, no wonder the numbers are dwindling and the spectrum space is being sold to big business by the government.
Not caring for the despicable treatment of poor innocent unsuspecting souls who dared to come to this site and ask for help for their CB, and the endless hijacking of threads by people dedicated to impressing you with how much better they are than you I will try to help. You can connect the grounds between the external speaker jack and the PA jack with a fixed resistor ranging from 22 to ohms. The value will be determined by your radio model, choice of mike, and other conditions such as speaker type and placement.
You will need to determine this experimentally to get the right level of talkback and no, it will not affect your use of the PA function. A typical example for a noise canceling mike on a Cobra 29 would be to start around 68 ohms.
For a stock mike around ohms. Listen to the sound and go from there. If you have to lower your mike gain to stop squeal you are too loud, go to a higher value resistor so as to not excessively reduce your transmitted power. Rat was giving you a good idea except his choice of variable resistor is not all that optimum.cobra 29 lx-le modulation adjustment (vr4)
A volume control is typically 50, ohms, much too high. Actually the 1, ohm RF gain control already in there is a better choice as you will have a wider range of adjustment in terms of degrees of rotation of the control. However I for one prefer to have the RF gain function so I believe picking the correct value of fixed resistor is a better method.Log in or Sign up.
Find Trucking Jobs. Aug 26, 1. In the same year, I watched the tech. Nothing else. Then he checked my swr on my antenna set up.
And I was good to go. On a quiet day I have spoken with other trucks anywhere from 7, up to 12 miles away. I used that radio for 6 year, daily. This tech cut nothing, added nothing. He just melted the wax and adjusted 2 coils on the speaker side of my radio.
What 2 pots did this tech adjust? Any idea? Thank you, Jimbo. Yes, let employers and TruckersReport text me with new opportunities, job alerts and other career information to the number I provided. There is no charge for this service, but standard message and data rates may apply. Aug 26, 2. Aug 26, 3. Without seeing what he was doing it's hard to tell. There's so many pots inside of a radio Did this so called tech put the radio on an oscilloscope?
Did he also have said radio on a signal generator? Turbo-TAug 26,