8 volt source? Uniden Pro520xl

[Cutlass327]

Trying a new echo board, a Ranger EB-2015. It has "DC input 8v" for the power connection that you usually put to the radio on/off switch.

Is there an 8V source, or is this just put to the power switch like normal?

If there is, I need an 8v source on the 520xl and a Cobra 25 NWSTWX if at all possible?

 

[nomadradio]

Don't worry about finding a source of + 8 Volts DC.

That board has a voltage-regulator chip on it. Should tolerate running from the radio's main 13.8-Volt power just fine.

73

 

[Cutlass327]

Awesome, thanks!

This is one of those new models, very spacious for its size...

Also looks like the tuning for the old ones won't work. There are 3 pots right in the middle, one labeled TX power, one RX, and one Squelch... Odd they made them so easy to find.

 

[nomadradio]

What makes it look spacious on the component side of the circuit board is that the parts are all (nearly) on the solder side.

The Tx power trimpot is for the meter, not the actual transmit power.

73

 

[psycho]

Coibra 25 soundtracker and a 520XL????? At least you won't be ruining good radios.

 

[Cutlass327]

Start simple, right?

Don't want to ruin my Galaxies while refreshing my brain on this stuff.

 

[Shadetree Mechanic]

I run a 510 in my stake body truck. It has never failed me. Modifying the radios is what hooked me on the hobby. More power to you.
Chris

 

[psycho]

Start simple, right?

Don't want to ruin my Galaxies while refreshing my brain on this stuff.

I don't know where you can put an echo in a 520, you might need to sticky tape it to the top of the case. LOL

 

[Cutlass327]

I don't know where you can put an echo in a 520, you might need to sticky tape it to the top of the case. LOL

This one is small. I dont think it is even 2" square. There is also a little bracket on it and a screw to bolt it to the side of the chassis. The hardest part is to figure out where to put the controls!

The radio itself is a lot of empty space inside, all surface-mounted components.

 

[Cutlass327]

Well, I got it in there. The eBay seller "s9cb_radios" who I bought it from helped me out a lot! There is a voltage regulator on the side of the chassis under a metal cover that has the line in volts, ground, and 8V output. Hooked it to that, it worked. Had to turn the output on the echo board to max, but wasn't happy with what I heard over my base radio - wasn't clear and loud. Same board in the 25 sounded perfect, and didn't have to turn it up. Dunno if it has to do with the "high impedance microphone" part of the 520. I took it out. And for what it is worth, a 68 Ohm across PA and Ext speaker worked perfect for talkback, even though I had found somewhere on here someone said it didn't work.

I'm putting that board into a 2nd 25 I have, maybe I can fit it into my Focus where I squeezed the 520...

 

[Handy Andy]

The 520 uses a Electret Mic - supplied power by the Mic wire to the Element and audio - got both power and audio thru the mic cord as you use it.

So perhaps your issue was with the Electrets' Power interface - that can screw up the Echo real fast.

You have the SMD (Surface Mount Device) board in there. This makes it tougher to choose where to inject as well as sample the audio. All the traces and parts are on the bottom - or top - depending on how you mount the radio and use it.

Now had you used the Echo boards own Mic Amp, it's strong enough to drive the Audio amp directly - you can remove a couple of mainboard parts to allow the audio into the Echo Board without the headaches and the "other side" (output) of the parts would be the continuation of the audio path from the Mic into the rest of that radio.

You chose the more dedicated route of the Cobra 25 - you should be ok in that scenario.

But, I'm only letting you know that they threw you a curve by having the radios' Mic get power from the radio thru the audio line to power the element. This method was so they can save $$$ by not having to have a ton of support parts for the mic amp and limiter tie ins' - just the Electret gives enough power to drive an audio amp directly - kinda' like a turntable - Magnetic Cartridge requires PHONO input amp (low level) while Ceramic Cartridge gives you Line-Level (Tape Monitor) output. Why fuss with all that low-level amp stuff when you can just run a power mic on a 3V power source using an Electret instead.

Good luck on your project.

 

[Cutlass327]

That would make sense. Thank you for the follow-up.

 

[nomadradio]

That's what this world needs. An echo board with support for electret mikes on its input side.

73