Uniden grant xl echo board removal

[red97k1500]

I picked up this grant xl about six months ago and it works... and the echo board works as well. I just don’t like echo boards, and I don’t want it in my grant xl. I really do not want to buy another grant xl just to put this one back to factory. If any one can help me by looking at their grant xl and telling me where the wires go I would greatly appreciate it and I will even give you the echo board if you want it.

I know the brown and white wires go to the internal speaker, I do not know where the black and white wires go, they where just clipped off at the ends and tucked into the wiring in the radio.

I need to know where the blue wire coming off the mic gain control goes. I know that it ultimately goes to pin 1 on the mic jack but I want to put it back to the factory spot.

Also the spliced into a white wire going into a 3 wire connector that is right by r260 and c100.

Thanks for any help anyone can give me. And you don’t have to be a radio guru to help if you have a grant xl and a cellphone camera that’s probably enough.

 

[red97k1500]

Better pictures, the echo board is a eptossb50 that I’m guessing is made by rci, and probably from the 90s, so now it’s vintage, rare, super cool, nos, mint condition lol. Don’t miss out on this super duper duper duper duper echo board

 

[Handy Andy]

This is the best I can do at the moment...

While CB Tricks was working, and I had a stable environment to work on some radios - I started gathering up documentation on radios that I have in my collection so if the case ever arose to get back to them I had documented the board to show layout.

Right now the Wife has my stuff buried under Moms' stuff that has to be sorted thru.

But...due to the nature of having to go thru THAT stuff to get to my OTHER stuff that is underneath all of MOMs' stuff. Simply put - I'd have to commit myself to possibly entertaining the ideas of Preservation of Life, including my Health, which may include Isolation and sending myself to spend time in ICU amongst other options which are just as harsh if not harsher - unless I don't survive the wifes' gentle corrections...

...Then it's nice to have known you...

 

[red97k1500]

Thanks Andy,
Can anyone tell with certainty, if the white wire that I marked in picture below is going to
The mic gain control?

 

[Handy Andy]

Before I say yes...

There is a section of that board, close to the side panel - that the jumper for that white wire goes to...in your pic snapshot - it's the jumper that heads SOUTH in that pic - heads towards the side panel - on Mic Jack side - note C108 - that is part of this branch that in this setting - will COMBINE with Mic amp and PA amp but you select this side of these amps are used.

Were you able to get the CB/PA switch wired ok?

Reason? Because of where the Mic Gain is, that pink wire runs off the center leg of that pot. That's the live wire variable.

The 3pin header looks to be the CB/PA setting to make sure the proper Mic amp stage is operating.

Why the side panel? Please make sure that white wire is the CB / PA switch - for that handles TR27...PA Amp there is a switch that Enables/Disables - routes audio that turns off the Mic amp for SSB/AM but routes that audio to the Audio amp chip .

Make sure they did not set up talkback using the PA switch.

 

[red97k1500]

The cb/pa switch is factory, all the switches appear to be factory, there is no channel mods done to this radio. Talk back was done with a resistor on pa and external speaker jacks. Really the only mods at all that I can find on this radio is the echo board. I think the white wire from the three pin header, is supposed to go to the far left tab on the mic gain control. Right now there is a blue wire soldered to it that is connected to the echo board.

 

[Handy Andy]

Ok, good to know, and you've made progress.

All I've got here right now is a PC78 - can you work with me, using this wiring scheme - on this radio or would you rather wait for someone whom has a XL?

 

[red97k1500]

Hey Andy thanks for your help, I have a pc78xl and 3 different cobra 148s, but none of them seem to be similar enough to help.

 

[Handy Andy]

Well,. I see and hear ya' callin' but my hands are tied until the XYL can let go of the mess so I can help.

Right now I have two rooms full of Moms stuff and her support (medical equip) that we somehow got here and now we can't get rid of it because the XYL wants to "Sell it" and we already know (the rest of us) that used medical equipment doesn't get sold, except for scrap.

SIGH...

 

[red97k1500]

It’s no problem, I appreciate your help. and one of the pictures you posted did help me.
If anyone else out there has a grant xl and doesn’t mind removing a few screws and one cover i would greatly appreciate it. I’m really only trying to figure out where three wires go.
I would really like to figure out where these two wires go because the clipped off at the other end, I don’t believe they even have anything to do with the echo board at this point, but I might be wrong. I know I’ve posted a lot of pictures but then I keep thinking well maybe it was a bad picture lol. These are the two wires below. There near jv23 kinda of close to the voltage regulator.

 

[red97k1500]

Bump, I can take any picture of any part or wiring on a factory unmodified cobra 2000 that any body needs if they can get me a picture of a uniden grant xl.
I want to know where these two wires go to.

 

[red97k1500]

Six years later I’m bringing this thread back, I basically put this radio away six years ago and have not messed with it since.I removed the echo board six years ago. I remember that talk back had been added using a resistor on the ext speaker jack, I removed that resistor back then. I was able to reconnect all the wires with the help of members of this forum.

Fast forward today, the radio still has talk back, I messed with radio yesterday trying to figure out why, in am mode I can hear myself coming through both the internal speaker, and an external speaker, if I plug one in. And the talk back gets louder the more I turn the mic gain up.if I turn the radio to side band the talk back is still there, but garbled. I have looked over both sides of the board really well yesterday, looking for obvious talk back mods, cut traces none factory resistors etc. all I found was r131 has been clipped out, tr24 tr25 tr26 are all intact, the radio has no channel mods, clarifier is unmodified. I’m trying to put this radio back to factory.

This is a pb208ad uniden grant xl, what schematic does everyone use for this radio,
There is a schematic for a grant lt on cb tricks, I figure that is at least close to a grant xl, then there is the 148 gtl redrawn schematic from 2008. Then there is the pb-412 cobra 148gtl, I don’t know which is closest to a late model grant xl.

 

[MKwrench]

Sometimes it's the mic. or related jack board. If it does not unground the RX pin, you'll get a talkback effect. Take a peek let us know what you find.

 

[red97k1500]

I don’t believe I’m dealing with a microphone problem. The microphones I’ve been using to test with, work perfectly with my old school McKinley two other 148 gtls etc. and I believe are wired correctly.

I have done some more testing this evening, I seemingly don’t have any talkback without an external speaker plugged in and using the radios internal speaker. If I plug in an external speaker I get talk back, no matter what microphone I use. The talkback is loudest in am. If I plug in my Astatic d104 tug8 and turn the radio to lsb or usb the radio instantly starts squealing. It does not squeal in am.

I noticed another thing with the volume all the way down and the mic gain up I can still hear my self. I looked at the back of the mic jack I don’t see any pins shorted solder blobs or any thing that looks like a mod. I do remember that who ever owned this radio before I got, it had added talk back with a resistor on the ext speaker jack.

I think what I’m dealing with now is not a modification, but possibly an actual fault in the radio possibly. A short somewhere, a failed component. Or possibly something I unintentionally did while removing the echo board.