Question about Cobra 148 GTL 120-Channels Base CB Radio

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148gtl, Taiwan when you modulate the meter swings backwards

Hello,I took this radio in for repair everything worked but there was no power or movment in the meters when keyed,so caps C95,109,173,174 was replaced and that brought the radio back to where it keyed up but only keys a 1/2 watt,the repair guy never finished it,he goes south for the winter.he said that the finals were putting out what they should,and the regulater also..Here is the specs on the radio..PCB 412,PLL MB8719..final is C1969 can you tell me what else I need to replace? on SSB it swings forward but its not powering up all the way.Can you help?

Thank you so much

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  • AnyMHz.com
    AnyMHz.com May 11, 2010

    yes more info please sounds like a dead key of 1/2 watts.

  • Tom Arsenault
    Tom Arsenault May 11, 2010

    1/2 watt deadkey or 1/2 watt swing? Has the power mod been done to the radio? Has a "modulator" or "super tune" been done?

  • Steve Tompkins
    Steve Tompkins Mar 14, 2013

    The idea is on AM Amplitude Modulation- You need full power to get high performance-its all audio modulation& antenna- AUDIO Mods make sthem super loud with only 1 1/2 watts of power- so the key is turned back some by old timers.

  • Steve Tompkins
    Steve Tompkins Mar 14, 2013

    Sorry I meant to say"You don't need full power of 4 or 12 watts SSB- You just need 100 to 130% modulation by Power Mics or Modification of Audio mod(swing)Setback dead key to 1 watt to 1 1/2 is the old timers way.

  • Steve Tompkins
    Steve Tompkins Mar 14, 2013

    Loudness is the result of setback 1/2 watt. But to clear it up& further range is to give it 3 watts deadkey.

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In the back is where power mods have been added...It sounds like a swing kit 1/2 watt deadkey to 25 watts which is a powerful modulation exceeding 100%. Its a 220uf capacitor in place of a jumper J1 or J(x) J something in some radios. if you replace the jumper and remove the capacitor 220uf or 470uf one.(near finals it will return to around 4 watt dead key) The result of 4 watts is modulation is flat;where if you adjust it to 2 1/4 watt to say 20 watts it will be very loud and modulation is at 100%.

Posted on Jan 06, 2012

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