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2 Broken CBs

Discussion in 'General CB Services Discussion' started by Defiance665, Jul 15, 2010.

  1. Defiance665

    Defiance665 Web Wheeler

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    My friend has a Midland CB, I think its a 77-882 40 channel.
    It has lost channels 10-40, but sends and recieves fine on 1-8. Any Idea what the problem is, a possible fix, or just junk it?
    If he cant fix it I guess he'll have my 23ch Hygain V MKII for a while until he gets some money around.

    I have a Midland 77-120ESP2 that makes that speaker "click" noise when you turn it on, but no other signs of life. Any Ideas? Junk it or what?
    I have a working 77-120 in my Jeep and like it alot, I would like to try to find out whats wrong with this one but I think it may be dead.

    Thanks,
    Dylan


     

  2. Wire Weasel

    Wire Weasel Senior Moment

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    Junkity junk junk....sorry

    Rip 'em a part and start ya a parts bin
     
  3. Defiance665

    Defiance665 Web Wheeler

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    Thats what I thought, but figured I would ask.
    I got 1 working 77-120 and one broken one for 10$ off ebay, so I guess its not that bad of a deal.

    Looks like my friend might be getting the hygain for a while.
     
  4. fodendaf

    fodendaf Active Member

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    try some wd40 or switch cleaner on the channel switch. You could be lucky.
     
  5. Defiance665

    Defiance665 Web Wheeler

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    Its not the selector, When he talks on it I can hear static with a tiny bit of his voice. Very quiet too...
     
  6. office888

    office888 Active Member

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    TX on 10-40?
    TX on 1-9?

    Sounds like a mostly failed component.

    -Richard-
     
  7. Defiance665

    Defiance665 Web Wheeler

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    TX and RX on 10-40 are pretty much gone.
    1-9 Are fine.

    Ill just tell him to pitch it next time I see him.
     
  8. office888

    office888 Active Member

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    Is it putting out full wattage with no modulation? 0.3w? No watts?

    His radio sounds like it might be a broken crystal, as I'm not sure how many xtals there are in the 77-882. Or maybe the PLL chip failed.

    Your 77-120, I'm not too sure, but there's probably a failed component on the board. Does the PA function still work?

    Let me know if you're going to trash both, I enjoy tinkering and since you're in Michigan, I'll gladly take them off your hands. :)

    -Richard-
     
  9. Defiance665

    Defiance665 Web Wheeler

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    Im not sure, Ill have to have him get his meter out next time he comes over.
    Its almost 40 years old, maybe its a bad crystal or something.

    No PA on the 120, just a spot for an external speaker and a S-meter.
    Nothing works on it. You turn it on and hear a click through the speaker, thats it. No Display or anything.


    Youre about 3.5 hours from me.
     
  10. jazzsinger

    jazzsinger Bullshit Buster

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    sounds like someone has been arsing around with the vco coil.
     
  11. jazzsinger

    jazzsinger Bullshit Buster

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    wd40 is the last thing you want to spray into any radio,proper switch cleaner is a much better proposition.
     
  12. psycho

    psycho Running a special on our rooms!

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    WD-40????????? Do you even know what WD-40 is for heaven's sake??????? Why not just spray engine degreaser in the radio????
     
  13. office888

    office888 Active Member

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    Because diluted sulfuric acid is much better. :laugh:

    -Richard-
     
  14. Cityboy

    Cityboy Active Member

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    If you have some soldering experience and a bright LED light then you could try to troubleshoot this radio on your own. I cant find the info but I will assume it is a PLL for the fact 1. it is a 40ch(but not always the case) and fact 2. only 10-40 are being affected where as a crystal driven radio would have a problem with ever 3rd or 4th channel. So you if you can locate the PLL on the board then try pressing on the PLL with an eraser head of a wood pencil or a hard plastic utensil and try keying up the radio on those channels, if that doesnt work locate the crystals in the radio which there will be a least 2 and possibly more considering this is an eary 40 ch radio made around 1977 or so and if you locate the problem then take your soldering iron and heat up the joints where you found the problem. As far as your 77-120 it could be a couple of things from a $1 fix to a $10 fix if your willing to play with it. I would start by pressing around on the pcb board and see if it comes back to like and if it does then you have a cold solder joint and will have locate the joint that needs to be reheated and fixed. If it doesn't come back to life while light pressing down on the pcb then start looking at the rectifier diode and then the final transistor. Good luck.
     
  15. Defiance665

    Defiance665 Web Wheeler

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    I might of found the problem with the 77-120...
    On the right side of the board there is what looks to be a transistor, but it has 5 pins. Not sure what it is.

    Anyways, within seconds of the power switch being turned "on" it gets so hot I cant touch the metal on the other side of it.
    I emailed Midland a couple days ago about a service manual, they havent replied.
    Ive done some poking around and got a sign of life: If it hasnt had power applied to it in a while it will beep when powered up. After that its dead again.

    My friend wont let me touch the 882, his dad gave it to him and I think hed rather junk it than have me tear it open and try to fix it.
     

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