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President madison/ not working

Discussion in 'CB and Export Equipment and Accessories' started by mustang_gt_350, Jul 26, 2013.

  1. mustang_gt_350

    mustang_gt_350 Member

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    Hello everyone,
    I'm new to the forum, and new to the world of CB's and working on them. I have spent alot of time when i was way younger listening to the locals at night before i went to bed and have always been interested in tinkering. I would like to get my HAM lic. and figured the cb would be a good place to start out. A co-worker gave me his fathers old radio stuff, a model 29, a old midland and the madison you see in the vid along with his base antenna. I got the antenna mounted and have the mast grounded just as his father did except i still need to pound a grounding rod and attactch the ground. for now i have the copper ground stuck about 8" into the ground. A friend of mine just recently got into CB'ing and i figured i would dig out the madison and the other stuff and get it all setup since it was a nice not so hot day today.

    Ok so here is whats going on.

    madison cb - YouTube

    I can receive but it doesn't seam to be as strong as my truck with the 102" but i think that is from the base not being tuned and the whip on the truck is. I would have it tuned and plan on it but my friend has my meter.



    It sounds like the volume needs cleaned since its scratchy? Where would you start first with this?

    This is the 4 pin mic. Would there be any chance the mic is wrong and thats why it won't transmit? There was a midland mic connected to it when i pulled it out of the box.

    Thanks
    #1
  2. Robb

    Robb Yup

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    IIRC, the 4-pin Madison uses the 858 PLL chip. WHich is a nice radio to work with - provided it works in the first place. They are all getting very old at this point; so they need TLC to bring them back. The problem of no transmit may be as simple as the failure of the keying transistor, a diode failure, or a faulty electrolytic capacitor. You will need to get the schematic for it and trace it through to find the fault. If you don't have the experience or tools; then it might be time to punt.

    If you care enough about this old classic; then it might be worth it to send it to a shop and have them check it out, fix and clean, and then have them align it. That is something to consider. It's a keeper - only if it is up to snuff . . .
    #2
  3. mustang_gt_350

    mustang_gt_350 Member

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    alright, thanks.

    I'll have to pull it apart and see if i can dig up the schematic. I want to see if the board is full of corrosion. If it is it will probably just be a chasing one problem to the next.
    #3
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  4. roadrage

    roadrage Active Member

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    These old Madison radios are awesome. Some of the best ever built. It is common for these to have problems with the caps, due to their age. There are capacitor kits available for them for about $25. Just make sure you get the right kit. There were 4 versions of the Madison. I just got myself a 4th generation Madison and sent it out to have it gone over and aligned. I have$2oo into it including purchase. If you get it working, you are lucky to have had it given to you. Mine in the crown jewel of my radio collection. Good luck with it. I hope it is just a simple fix.

    The older Midland radios, even though they had 4 pin microphone jacks, weren't wired the same as the standard Cobra/Uniden type. They looked the same, but were just wired up backward. Try taking the mic from your Cobra 29 and hook it up to the Madison, see if it will transmit. Its worth a try.
    #4
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  5. loosecannon

    loosecannon break on through

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    you may have the wrong mic, or you may have a radio problem.

    go to CBTRICKS.COM and look up the cobra 138xlr or the cobra139xlr.
    these radios will be almost identical to your madison on the inside, and will show you the correct mic wiring.

    just check the jack on the mic with an ohmmeter to see if its wired right.

    if that doesnt work, post again and be as specific as possible when describing the problem.

    no TX, does that mean carrier with no audio?
    no carrier at all?
    does the TX/RX light switch over when the mic is keyed?

    does it work in any mode? USB, AM, LSB?

    LC
    #5
  6. sonoma

    sonoma Well-Known Member

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    also check that the relay is switching when you key the radio.
    #6
  7. mustang_gt_350

    mustang_gt_350 Member

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    Ok i will be able to tinker with it today but it won't be until later tonight. Right now with the mic that was hooked up to it (midland) When i key up There is a small click in the external speaker but it continues to produce sound. No TX light, No carrier/audio. Its just like you haven't even keyed the mic at all. I'm wondering if its isn't the mic being wrong, or the relay isn't working. This is in all modes.

    I just have to locate my damn meter, it always walks off somehow.

    I'll check those things later tonight and post back.

    I also have a cobra 19 that i know for sure is the mic that goes with it as i bought it new and it came with the radio. Will this work the same as the 29's mic? The 29 didn't have a mic on it it came in the box with the madison.
    #7
  8. roadrage

    roadrage Active Member

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    Yes, the Cobra 19 mic will work the same as the Cobra 29. It is pretty much the "standard" 4 pin that most (4 pin) radios use. I don't know why many (not all) of the Midland radios are wired differently, but they are.

    An example, I bought 4 Midland radios at a yard sale for almost nothing. Only one had a typical 4 pin microphone jack. I took a Cobra style mic from my shelf to attempt to test the radio. I turned it on and the meter registered like I was transmitting, only I hadn't keyed up. When I did key the mic, the radio clicked and the meter dropped to nothing. I researched and found that the wiring was different on the Midland radio. It wasn't working improperly, I just had the wrong mic for it.

    I am not saying this is what is happening to your radio, just that it is possible. If you have a stuck meter (which is also a common occurrence) it could be that you just can't see it happening. It may end up being a bad cap or relay, but may as well rule out some easy things first. I'll keep my fingers crossed.
    #8
  9. mustang_gt_350

    mustang_gt_350 Member

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    You were right, I pulled the mic from my truck, tossed it onto the madison, and when i key up i can hear the relay click and the TX light come one. Now the meters are stuck, and being that i only have one mic i can't do any test to see how the sound is from my truck to the base and the other way. I have a cobra power mic that is in the box but its a 5 pin. I do have another cobra 4pin that isn't working as its not allowing sound when its plugged in. I'll have to tear it apart and investigate. Is the 5 pin able to be rewired into a 4? if so i'll give that a shot (y) Looks like my free radio may have been a AWESOME score along with the old school penetrator, and the model 29ltd and the midland 2001. They all work, as the 29's problem was also the mic. :drool:

    Now that the 29 is working i can get a decent idea of the swr of the base antenna.

    thanks again.

    THanks a bunch for the help. I never knew that the 4pins were diff.
    #9
  10. mustang_gt_350

    mustang_gt_350 Member

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    checked the swr with the cobra its saying 2.9 on 40 and 2.2 on 1. Looks like i'll have to do some tuning.
    Last edited: Jul 26, 2013
    #10
  11. roadrage

    roadrage Active Member

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    What model power mic is it? You should be able to re-wire it to a 4 pin.

    That Penetrator should work well with that radio. I have Radio Shack's knock off version of the Penetrator 5/8 wave (actually a .64 wave) GP antenna and it really works well. My step father had it on his camp roof since the 70s. He wanted the tripod for a small windmill. He just heaved it down and busted it up pretty good. I almost killed him when I saw it. He gave it to me and I restored it. I spent a lot of time straightening out all the bends and twists. I had to replace on ground radial and had to fabricate a new matching network for it. It is nothing short of amazing. I only tested it so far, on a 4ft pipe I hammered into the ground. Even at ground level it amazed me at the difference between it and my 102" on my truck. I just recently was given a 50' tower so I can't wait to see what it will do then. Only I have to wait 6 months or so before I can set it up.
    Last edited: Jul 26, 2013
    #11
  12. mustang_gt_350

    mustang_gt_350 Member

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    cobra ca-76

    So following that link to the cbtricks page it says it can be rewired to work following this?

    Cobra CA Series
    1- Shield & Black
    2- Red
    3- White
    4- Blue
    #12
  13. hotrod

    hotrod Well-Known Member

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    The older Midland radios, even though they had 4 pin microphone jacks, weren't wired the same as the standard Cobra/Uniden type. They looked the same, but were just wired up backward. Try taking the mic from your Cobra 29 and hook it up to the Madison, see if it will transmit. Its worth a try.[/QUOTE]

    try this first. then try tuning the antenna. the recieve in radio may need tuned
    but they are a quiet reciever
    #13
  14. mustang_gt_350

    mustang_gt_350 Member

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    try this first. then try tuning the antenna. the recieve in radio may need tuned
    but they are a quiet reciever[/QUOTE]

    The 29's mic doesn't work either. That is what was giving me the problems. I had swapped between the midland and the 29 on the madison. So the mic that does work (midland) isn't compatible with the madison, and the 29 that is compatable isn't workign correctly.

    I will try to fix or rewire another one to the correct 4 pin for the madison and then i can try between my truck and the madison. I plan on trying to tune the antenna tomorrow morining and rewire the mic's later tonight.

    Is the recieve tuning somthing that i can do?
    #14
  15. mustang_gt_350

    mustang_gt_350 Member

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    Great, i can't wait to get it tuned into a resonable SWR and give it a try. Mine is on the first story roof and ontop of a 9 or 12' pole. So that puts it around 20-25 feet plus the hight of the antenna. The radials are just a few inches above the peak of the 2nd story roof.
    #15


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