cobra mods newbie (trying not to ask the same questions)

greasemonkey85 · Post by **greasemonkey85** » Monday 23rd Apr 2007, 12:45

hey fellas, i am going to try this mod

http://cbradiomagazine.com/March%202007 ... cation.htm

and i would like to hook it up to the rf gain to make it variable. is this what some people call the variable power and make you pay $20 for on ebay?

where do i hook the rf gain to then, it doesn t say much?

i also found this

http://www.dtbradio.com/wholesalecobra.htm

scroll half way down to cobra 25 & 29 variable power

what is the point of using a TIP120 transistor instead of the 220 uf capacitor?

also i would like to do the final & driver upgrades, i know where to them at, i would just like some one to help (tell me) how to do it?

i am the kind of person that would like to spend $10 or $15 on parts and do it myself then let someone else put a "kit" together for me, or have them do it for more the twice the amount of money.

thank you, this site is awesome!!!!!!!!

kc8mob · Post by **kc8mob** » Monday 23rd Apr 2007, 14:29

Well the kit you're referring to with the TIP120 in is very very universal. You can install that in any radio and effectively get a super swingy result

For your cobra 29. There is a thread here where I have gone over this in detail.

For variable power, all you have to do is use a pot instead of fixed resistor. Using the RF gain control is quite easy. Just trace the wires from the pot back to the board. Pull them from the board and use the wires where you would install the resistor. Then take a jumper and put it in the holes you have left from the RF gain circuit.

Pretty easy.

greasemonkey85 · Post by **greasemonkey85** » Monday 23rd Apr 2007, 14:32

could you post the thread if you find it?

that makes sense, i couldn t figure it out, so instead of putting the resistor in you just wire the rf gain! got it

Turkish · Post by **Turkish** » Tuesday 24th Apr 2007, 6:08

DO NOT cut D11 it will make your radio sound like shit just adjust VR4 all the way clockwise.
Also I just dit the "super swing" mod on my cobra it works like a champ but I had to find the right resistor in my case it was the 220ohm 1/4 watt.
if you dont like your results change your resistor value and test it again.
Also let me know how the mod works for you and what you used in it.

kc8mob · Post by **kc8mob** » Tuesday 24th Apr 2007, 11:55

I take it you cut D11.

If you cut D11, your carrier has to be atleast 2.5 watts or your audio will be garbled.

Turkish · Post by **Turkish** » Tuesday 24th Apr 2007, 12:01

No I did not cut it. I removed it with a soldering iron and then replaced it when I realized my mistake. I am very glad I did not cut it.

greasemonkey85 · Post by **greasemonkey85** » Tuesday 24th Apr 2007, 14:24

ok well i didn t cut the d11, but i did remove it,

i also found that when my tech peaked and tuned it that he cut r55, i don t know why or what this did.

so here is what i did, i jumped d8, put a 220uf cap across j36 and also hooked it to the rf gain. man this is awesome!

when i got it peaked and tuned it had a carrier of 5 watts and swing to 18watts, ow it i can adjust the dead key to 0 watts up to 8 watts and it will swing to 20 watts. rms is 10 to 12 watts. man i can t believe what this did!!!

i have another problem but i will address this in another thread.