Question about Cobra 148 GTL 120-Channels Base CB Radio

1 Answer

Schematic diagram of cobra 148 gtl cb radio china made

I need it for expanding the band

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  • 5 more comments 
  • Iron
    Iron Nov 10, 2011

    If you can comment up here because a bug won't let me see what you have wrote.

  • HARTA ADHI BHIRAWA Nov 10, 2011

    The PLL IC is MMB 8719,is it the same with the MB8719?

  • Iron
    Iron Nov 10, 2011

    Yes, that is correct. in the schematic it is labeled MB8719. This is the PLL. A fair warning, if you fool up doing this you will need an O-Scope to get the radio oscillating again. Take your time. Also when you are done soldering, pull the power cord, turn the radio on and let it sit for a minute. Then re hot glue the PLL area and let it set for an hour to dry to a solid again. Then you should be good to go.

  • HARTA ADHI BHIRAWA Nov 10, 2011

    Thank you,that would be helpfull

  • Iron
    Iron Nov 10, 2011

    Your welcome. The reason you want to turn the radio on after removing the power feed is to let the capacitors discharge. you want to actually do this before soldering. Good luck.

  • HARTA ADHI BHIRAWA Nov 14, 2011

    Thank you Ironfist109 for your support,now i am able to hear and having dx contact,i wonder what is your callsign,who knows we can meet on the air someday,73 de 91 ON1174

  • Iron
    Iron Nov 14, 2011

    Glad I could get ya fixed up. 73

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  • Master
  • 3,018 Answers

  • Locate the MB8719 chip that is right behind the channel selector. Wire a SPST switch from pin 10 to ground and another from pin 11 to pin 12.


  • Channel Chart
  • Position 1: sw1 down, sw2 down
  • NORMAL CHANNELS

  • Position 2: sw1 up, sw2 down
  • 15=26.815 20=26.885 25=26.925 30=26.985(ch3)
  • 16=26.835 21=26.895 26=26.945 31=26.995(ch3A)
  • 17=26.845 22=26.905 27=26.955 32=27.005(ch4)
  • 18=26.855 23=26.935 28=26.965(ch1)
  • 19=26.865 24=26.915 29=26.975(ch2)

  • Position 3: sw1 up, sw2 up

  • 1=27.605 6=27.505 10=27.555 14=27.605
  • 2=27.455 7=27.515 11=27.565 16=27.475
  • 3=27.465 8=27.535 12=27.585 20=27.525
  • 4=27.485 9=27.545 13=27.595 23=27.575
  • 5=27.495

  • Position 4: sw1 down, sw2 up

  • 1=27.605 11=27.725 21=27.855 31=27.955
  • 2=27.615 12=27.745 22=27.865 32=27.965
  • 3=27.625 13=27.755 23=27.895 33=27.975
  • 4=27.645 14=27.765 24=27.875 34=27.985

Posted on Nov 09, 2011

  • 4 more comments 
  • Iron
    Iron Nov 09, 2011

    Here is position 4 with all of the channels ---

    Position 4: sw1 down, sw2 up

    1=27.605 11=27.725 21=27.855 31=27.955
    2=27.615 12=27.745 22=27.865 32=27.965
    3=27.625 13=27.755 23=27.895 33=27.975
    4=27.645 14=27.765 24=27.875 34=27.985
    5=27.655 15=27.775 25=27.885 35=27.995
    6=27.665 16=27.795 26=27.905 36=28.005
    7=27.675 17=27.805 27=27.915 37=28.015
    8=27.695 18=27.815 28=27.925 38=28.025
    9=27.705 19=27.825 29=27.935 39=28.035
    10=27.715 20=27.845 30=27.945 40=28.045

  • Iron
    Iron Nov 09, 2011

    Let me know if you have any questions.

  • Iron
    Iron Nov 09, 2011

    test

  • Iron
    Iron Nov 09, 2011

    test.......

  • Iron
    Iron Nov 09, 2011

    Good luck to you.

  • HARTA ADHI BHIRAWA Nov 10, 2011

    Thank you very much,but the PLL IC is MBB8719 is it the same with the MB8719?

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1 Answer

How do I increase power output for a cobra 148 gtl the latest Chinese version


best way is to leave the radio in piece and obtain a linear amplifier to do the job a 10 meter ham radio amplifier will do nicely but you must re-tune it for the 27 mhz band 10 meter band is 28 mhz.
RF amps work best using side-band mode.

Oct 14, 2013 | Cobra 148 GTL 120-Channels Base CB Radio

1 Answer

148 gtl cobra cb radio and the rx/tx light stay on


This sounds like a problem with the MB3756 Regulator IC. It controls voltage regulation and TX/RX Switching. It is a common failure in these radios. Check voltages with schematic that can be found at
CB Tricks Home Page

Sep 02, 2013 | Cobra 148 GTL 120-Channels Base CB Radio

2 Answers

Cobra 148 gtlcobra 148 gtl DX


http://www.cbtricks.com/radios/cobra/148gtl_dx/index.htm

Nice choice of radio i have the Grant LX Uniden which is roughly the older version.
This site may be of interest also if you choose the channel mod make sure you have the right PLL. http://www.radioaficion.com/HamNews/mods/mods-cb/2428-uniden-grant-xl-mods-pll-agc-power-clarifier.html

Nov 16, 2011 | Cobra 148 GTL 120-Channels Base CB Radio

1 Answer

I need schematics for cobra 148 gtl





  • When you get to the link click on "Click here to start download from MediaFire.." and the PDF will download onto your computer.

  • If you have any comments please feel free to leave them here.
  • Hope this helps and thank you for using FixYa.


Regards, Tony

Oct 12, 2011 | Cobra 148 GTL 120-Channels Base CB Radio

1 Answer

No modulation in AAM only mode. Needing a schematic.


if the transmitter produces power output with modulation on SSB but NOT ON AM then the AM Pass Regulator is defective, more times than not.

May 24, 2009 | Cobra 148 GTL 120-Channels Base CB Radio

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