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mattsowders1989
11-29-2016, 09:08 AM
Is it possible to do a direct injection mod on a 142 gtl? I would buy a 2000 gtl or a 148 but I can't afford it right now. Any help would be very helpful.


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doughboy
12-01-2016, 12:05 PM
Get a 1/8" Phono Jack or 1/4" or rca jack mount in back of radio get yourself a small piece of coax or shielded audio cable cable Center to Positive of the Phono Jack etc.. cable Shield or Braid to Negative of the Phono Jack etc..


other end of that cable Find capacitor c119 center conductor of audio cable to positive side where c119 was ground shield of audio cable to a nearby ground pretty much the same as 148 injection

doughboy
12-01-2016, 12:10 PM
also if you get hum or rf noise you can add a small capacitor at the end of the cable before going into the c174 location to filter off the noise

mattsowders1989
12-01-2016, 12:21 PM
What about keying up? I guess I should use the transmit pin and ground for keying? I've seen people make a box for it.


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doughboy
12-01-2016, 12:31 PM
Yeah you just use the regular mic jack ground and tx pin with a foot switch or button or even an old mic I don't member if that radio needs a receive pin or not unplug the mic if you still her receive your golden if not use and old mic or switch from a mic to rig up something

mattsowders1989
12-01-2016, 12:32 PM
Cool. Thanks doughboy!!!


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mattsowders1989
12-04-2016, 08:09 PM
i cant find c119 for the life of me. when i do find it, do i need to remove it?

doughboy
12-05-2016, 12:15 AM
It should be not to far from ic4 ic4 is marked ta7222p also near tr35 and yes you remove then you audio feed goes in hole where positive leg was cap will be marked so you can see positive pin

doughboy
12-05-2016, 09:37 PM
Did you find it look at the pic in this URL it's on the right side you'll see a large chip heatsinked to the side that's the audio chip slightly toward the back from that there's a large cap it will be somewhere in that area

https://www.google.com/search?q=cobra+142&client=ms-android-verizon&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiCu6jWw97QAhVJOSYKHYwUBUwQ_AUICCgC&biw=360&bih=518#imgrc=V1rxXUG-0PQ2TM%3A

mattsowders1989
12-05-2016, 09:41 PM
ok. i did exactly what you said but i get no audio from the cable i ran. i ran from positive side of c119 and grounded the other. am i missing something? i key up the radio and send signal into the newly installed audio line but nothing comes out

mattsowders1989
12-05-2016, 10:02 PM
i just put the cap back in and i still have audio out of the stock mic jack with a mic hooked up

doughboy
12-05-2016, 10:04 PM
Are you sending in a line level signal like a mixer or something if so replace c119 back in the mixers probably to weak to drive it and go into the negative side of c83 that will leave some preamp circuit inline

mattsowders1989
12-05-2016, 10:06 PM
i was running an m-audio moblepre into it and it was dead as dead could be. it was amplified. ill try c38. is that close to the c119? remove its cap too? and negitive side, not positive?

doughboy
12-05-2016, 10:10 PM
Sorry I corrected my post c83 not c38 the reason c119 is not working it drives Darlington directly you would have to feed with like a 20 watt amplifier it's basically and external modulator setup at c83 you will use radios built in modulator but bypass most of the preamp

mattsowders1989
12-05-2016, 10:14 PM
oh ok. so remove cap on c83 and wire the lead to the negative side and then ground the other wire?

mattsowders1989
12-06-2016, 03:38 AM
Thanks doughboy! I ran my audio lead into the negative side of c83 and grounded the shield. My M-Audio MobilePre is running into it. Sounds really good. Thanks!


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