Maxon MCB-30 40-Channels Base CB Radio Logo

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Question about Maxon MCB-30 40-Channels Base CB Radio

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No power I have tried to hook up my Cb to my truck but when i hook the positive and ground wires my Cb does nothing? any easy solutions would be helpful thanks.

Posted by kwhittington on


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I think that you may have a power supply problem. I want you to first attach the antenna and then power up the unit. If nothing still happen, you will have to have the unit serviced. I would suggest that you get a schematic for the unit and then if possible get one of the shops on FixYa to take a look at your device. The reason I say this is because there are no user serviceable parts in the unit, and to open it up without having electronics experience is not adviseable. Thank you, Shuttle83

Posted on Sep 07, 2007


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I have a Vintage kinematix reverb with 5 wires red,yellow,white,brown and black how I hook it up what are the wire? it also has a delay tuning knob

usualy you have a transmit recieve switch
like this
RX <<-- >TX ptt

so three wires
the ptt button common in a cb with 4 pins is also ground
should be
black screen and i think brown
but you need to meter out the ptt common and RX TX
for rx audio switched radios then one pin is RX one pin is TX one pin is common or ground for the PTT and also ground for the screening copper braids and also ground for the transmit audio
so you have 5 wires
3 will be PTT 1 will be audio and one audio ground
usually white or yellow
so i think black and yellow or black and white
black being ground

just look up the schematic or service manual for your CB
and check out the 4 pin plug config
there is only two usual ones
cybernet or uniden so.. easy stuff
look for like cybernet cb 4 pin wireup in google or similar
remember just meter out using the beep test range on a cheep multimeter too see which three are the PTT
so the common of the ptt needs connected to the copper screening and also to the black wire all to the ground pin on the 4 pin plug
you can short from the ground pin on the cb side to its TX pin and the set will enter tx mode
same with rx audio enable {if uses most cb post 1984 dont use RX audio hard switching}
so just three pins to worry about

How do you install a Maxon radio repeeter. It only has two wires that apear to be a Hot(Red) wire and a Black(ground). Should I just ground it and hook it up to a power suply?

Your correct the red wire is the positive and the black is the negative. You must also make sure to use a power supply with enough current to operate the radio. Usually a 12 volt supply that supplies about 4 to 8 amps should do the trick

I have my cb grounded and a wire ran to the postive side of my battery terminal and the antenna wire ran and my cbs channels wont come up we thought it was jus my cb so we hooked another up and it did the...


Here is the deal, even with out antennas hooked up, you should get at least your channels on your cb showing, no of course you would have all noise and distortion with out antennas hooked up. And sense you hooked another cb up with same results it tells me, number one, it is not most likely your cb. If your channels are not even lighting up, then this tells me it is not getting power. I know you said that the cb is grounded, and there is a wire ran to the positive post of the battery. What I would do first of all make sure proper wire on cb is grounded and not reversed accidentally, but what i believe is your not getting power to the unit, if it was properly installed, there should be a inline fuse from the cb radio to the positive post the wire is connected to on the battery. I believe there is a inline fuse that is blow, or not a good connection on the post of the battery. To test this theory, take a long piece of same size wire gauge, and run direct from positive on battery to positive post on battery, of course making sure that the proper wire off the cb is grounded (must be grounded to something metal, might find different spot to ground the radio if not for sure on metal) If you get lights going on then on radio, then your problem, was not a good connection or inline fuse on positive wire that maybe you didn't see was blown. Let me know Mike

I think i shorted out my cb can i fix it

  • If you are referring to perhaps hooking up the negative and positive power wires backwards this should be an easy fix.
  • Remove the covers and look by where the plug plugs into the radio.
  • You will notice a 1N4001 diode on the circuit board. It will be black in color. This is the diode that blows when you hook the power and ground up backward.
  • Remove and replace with a new one. Pay attention to the "arrow" on the diode as it goes in one way only.
  • You can get two of them at Radio Shack for $2usd or so.

  • Hope this helps and thank you for using FixYa.
Regards, Tony

I have a Connex 3300. I do not have original plug (power). however, I do have one that fits. I need confirmation this is the right plug. It is three wires. One black(neg.) and two red (positive). I...

The center wire doesn't do anything. Its the outer wires. You can get a standard CB plug with 2 wires that will work just fine. If that plug fits, I it will work. My concern would be if the pos and neg are the correct sides. It should be, But I wouldn't know unless I looked at it.

DO NOT HOOK the radio up with the power wires backwards. Or you will blow the polarity protection diodes. They are there to blow if the radio is hooked up backwards.

If you look at the plug. There is a side the goes to a point, and the other side is square. The black wire, Ground, should be on the side that goes to a point. If it does, then that plug is standard.

It's fine to use and hook up in the usual way. Do not hook up the center wire. It does nothing in the radio. You can clip it, and put a bit of shrink tube on the end as so it does not have a chance to short on anything.

If you are not sure about hooking this power cord to your connex, just go on ebay, and get a regualr CB power wire. They are cheap. It should only have 2 wires.

I have everything hooked up but all i get is static. I had someone from radion shack check the ground and hookup and they said it all looked good. I have tried numerous CB's and different anntennaes still...

Truck boxes may be the best looking place to mount a CB antenna but in my experience they are the worst place for performance.

The 'ground' you need is not an electrical ground but an RF ground. The easy answer is that you need to mount the antenna to a mirror or the bumper or even use a magnet mount instead on the roof. The body of the vehicle provides an RF ground that the small truck box cannot. The only way it might work is to use flat, wide ground straps at all four corners of your box to the bed of the truck. You need metal-on-metal contact.

Lots of engine noise

I would check all connections it might have bin installed wrong

Need wiring digram for road king 56 to cobra 29 cb

He is actually looking for the Microphone wiring which is a roadKing Mic to the Radio Cobra 29.

Mobile Cobra CB Squeels on other people's radios when I transmit.

Hello winfieldweth,

Have you tried measuring the power output of your radio? If you do, I bet you that the power output is over 4watts PEP. This could be caused by a component changing value over time. What I would suggest you do is to measure the power first to see if the power is over 4watts PEP and then proceed from there. I don't believe it's a grounding issue since the antenna being used is made for a no ground condition. Now if you are planning to use a ground type antenna, I would suggest that you not do that, only because just grounding the antenna will technically do no good, since when the say ground what they are talking about is a ground plane no just a grounding point.

Check your power and then we can start repairing this problem.

I hope this helps, keep me informed on the progress.

Thank you,



Rebuilt heads on 96 blazer 4.3 now no power

Check your neutral switch, its usually on drivers side on the back of stearing column .Its easy to reach and if you consult a mechanics service book, it will be alot easier to find and save you alot of frustration. Please rate this. Thanx.
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