Question about Uniden PRO510XL 40-Channels Base CB Radio

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1987 uniden pro 510 xl

I have just purchased a Uniden Pro510XL manufactured in 1987, in mint condition. Like brand new, barely used.

I want to tweak and peak it. Currently it has a 2W dead key with no modulation. I know it will put out 4W with good modulation but all the mods I have found are only for newer 510's.

I would like a visual, schematic, or component ID, so I can find the 2.7 ohm final resistor so I can replace it with a .47 ohm, and where the heck are L5 and L6, they don't exist on my 1987 model? I did find D14 but I'm afraid to cut it and make an overmodulating radio that can't be understood. I just want to be careful with this old radio so I don't blow it up but at the same time I know these older radios can scream if peaked correctly.

Any help would be appreciated!


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Wow, from what you are saying, you should not be messing with the insides of the radio. Finals, are not resistors, that are TRANSISTORS, and they do not have resistance values at all.

The final is the little black transistor attached to the heat sink at the back of the radio. You can't just change the final. there are other parts that need to be changed if you want to do a high power mod. Don't even mess with it. you don't need too.

Next, D14 is not the uniden model. thats what you mess with in a cobra. Don't cut d14 in that radio or you will prolly blow it up. The diode you want to cut out is D203. DON'T CUT IT!!, Just un solder one leg of the diode. You won't be over modulated. That will bring you modulation up and your peak watts. it will swing to maybe 15-20 watts peak. That alone with make the radio louder.

You really don't need to raise the dead key. With a lower dead key you have higher swing. Its all about the audio. 2 watts for dead key is fine. Thats what I run.

You cannot do any other peaking with out a meter. If you have a meter you can spread the 2 coils behind the large transformer a tiny bit until you have peak wattage. L201 and L202. but from reading what you said, you should probably leave them alone, you will gain only a watt or 2, and its not worth it if you mess it up.

To be honest with you, all you really need to do is unsolder one leg of D203. Make sure you pull the leg out, and make sure it is not touching anything so it will not short.

Now if you do this, and it splatters, you can always solder it back in, and then turn RT201 all the way to the right, I think. If you turn it all the way to the right, and there is not modulation, you just turn it all the way to the left.

Please don't mess with anything else or you will screw the radio up.

Posted on Oct 03, 2009

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  • hazzard_coun Mar 20, 2011

    D14? my pro510 said to cut it for audio, however i dont have D14 in my radio at least i cant find it and yes the older pro510 has the D14 but as for the new ones i cant find it!!

  • Thomas Freeman Mar 03, 2014

    don't sped the coils at the back of the radio as they are for audio clarity . i just turn the VR and that should be good enough to much and your audio could clip .. look at

  • Thomas Freeman Mar 03, 2014

    oops never spread the coils !!


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