Uniden PRO520XL modification?

[Sinkhole]

Hello all, I decided to grab my OLD Pro520XL and D104 out of the garage with hopes of throwing it in my truck for an upcoming trip. Well I seem to have forgotten that there is no internal speaker and couldn't for the life of me remember why. So I opened up and this is what i found. a little home made circuit board soldered in and the speaker wires were cut. The broad has 6 100Ω resistors wired in parallel with a 100µF Cap. Can anyone tell me what this does and why.

 

[2FB327]

Just a guess, I don't know the radio, but probably a way to reduce the carrier so that they could run an amp.

 

[binrat]

Or possibly volting the final. Its been a few years since I have played with one.

 

[Sinkhole]

I bought in the mid to late 90's and. Kinda remember having it tuned, but it was never set up for an amp.

 

[222DBFL]

Look closer. The 2 cut grey wires look like it could have been for an echo board or channel expo kit maybe, I see 2 cut grey wires to the right of the board with the resistors and cap.

 

[CbRadiosPRONTO]

If you look closely, you can see a note that's says, "time to get a new radio".


CbRadiosPRONTO

 

[Robb]

Six 100 ohm 1 watt resistors in parallel equals 16.6 ohm dummy load for the speaker if hooked up to the speaker output. Have NO idea why someone would do this. What is it using for a speaker???

If someone was attempting to do the cap/resistor swing mod, they didn't do it right.

 

[Sinkhole]

The two grey wires are the speaker wires. So it's not a dummy load. The radio works fine when used with an external speaker. Just noticed the D14 Diode has been cut too.

 

[CbRadiosPRONTO]

Probably running it into a low drive car stereo amp


CbRadiosPRONTO

 

[Robb]

. . .Then I would guess that it is a swing mod/cap and resistor. After looking at the pictures once again, that would be my best guess.

 

[Sinkhole]

It's setup with an external speaker mounted to the bottom of it.

I was planning on just using it for 1 more trip then investing in a whole new setup. I will definitely be keeping the mic though.

 

[Robb]

If it is still working; then go with it.

 

[Sinkhole]

I was just kinda curious as to what kind of mod it was . Because I remeber having it tuned but not modded.

 

[sonoma]

the 520 radio is a strong sounding little radio for what it is after a peak and tune. I still have a 510xl that I ran for a few years and it still sounds good. recive is not the best without an external speaker on them. but they sound good on TX with a good mic. the stock mic is very good also but do not like how small they are.