Midland 4001 Fil / Out switch and wires off?

[dodgeyvanner]

Hi all
The "Fil / Out" slide switch is missing and I have no idea on the wiring for it, there are 3 wires off that I have shown in the pics:-
Black & red wires wound together coming from rear of board & a Black wire originatiing from the mic gain pot
Searched round the net but only managed to find a wiring diagram showing the wiring for a 3001 model not the 4001.
Could anyone post a pic or tell me please where the loose wires connect too and the wiring of the Fil/Out slide switch?
Hope the pic is ok, if not let me know and I will take some more as required.
Thanks in Advance!

mid1.jpg

[14CS06]

Hello

Schematic 4001UK













@+
Claude

[Cousinjack]

Fil/out is like a tone control..

If you want I can pull the lid off mine and take a picture ??

[dodgeyvanner]

Hi

Cousin jack - if you could pop the lid off and take a picture that would be great, thank you very much. The black wire comes off one of the terminals of the mic gain control and the red and black I am hoping are the same in yours as well.

Cluade, thank you for the schematic diagram, much appreciated as will be very useful.

[Cousinjack]

Ok... so

The small black wire that comes off your mic gain pot, goes to the centre 2 pins of the fil/out switch. Then from the top 2 pins ( if rig is correct way up) there is a green capacitor(?) which links to the yellow wire on the cb/pa switch..

As for the red and black twisted wires.... no idea as mine dosen’t seem to have those

[Cousinjack]

Photo’s

[Cousinjack]

Hi

Cousin jack - if you could pop the lid off and take a picture that would be great, thank you very much.

Also see : https://www.blunham.com/Misc/CB/PDFs/Midland3001etc.pdf

[dodgeyvanner]

Hi all,

Firstly, thank you for all the information and pics it has been a great help and I think using these I may possibly have identified what the red / black wires may be from, but will check with you guys if this theory is correct.

Have attached some pics of the other end of the red / black wires as to where they attach to which is 2 x resistors in series and a trimmer, I noted on the Blunham diagram at position R144 & R145 (where all this connects) that this may actuyally be a "Low Power" mod - what does everyone think is this what it is from what I have and the Blunham diagram?

R144 is a 10 ohm 1 watt resistor and the other resistor in series with it (Yellow, purple, browen, silver) appears to be a 470R resistor. The trimmer has 470R on it so the low power mod is what I am plumping for at present, so now assuming this was on a slide switch in place of the stanadrd Fil / Out switch. So this means that If i conect these two wires (twisted red and black) to a two position slide switch and fit that in the Fil / Out position i should be ok, assuming this is actually a factory mod as its shown on the blunham diagram?

If i go for the low power mod on a switch can i just leave the loose black wire from the mic gain pot disconnedcted?

midland4.JPG

midland2.jpg

midland1.jpg

[Cousinjack]

What advantage is the low power mod ?

[Cousinjack]

so the low power mod is what I am plumping for at present,

Easy way to check your theory....

If you (dare to) connect the red and black wires together.. does it lower the output power ?

[Cousinjack]

No, hang on, that’s the wrong way around, with those wires disconnected it ought to be in low power mode....

You’d need to join them to get high power..

[dodgeyvanner]

Hehehe you are as confused as me!
I havent fired the radio up yet so no idea if it transmits, with the wires off i wasn't sure if it would work as didn't know what they were originally for. Will fire it up tomorrow and see what if any output i have and come back.
No idea why a low power mod would be retrofitted as these came without the 0.4w switch so yes agree whh would you want to do that.

[ChubbyChops]

Back in the 80's when you couldn't find a clear channel you would go on low power and turn the gain down to be able to speak to people local to you.
These days with more channels than people, it's completely useless.

[Cousinjack]

If that does turn out to be low power mod, I’d pull all that out and go back to standard.. and install the fil/out switch again..

As useless as fil/ out is, it’s more useful than a low power switch .....

[dodgeyvanner]

Hi Cousinjack
After some tuning i have managed to get the rig to tx and it is a low power mod and you are correct the red and black wire has to be connected to get hi power so i can simply shorten the red / black wires and solder together. Will put the fil switch in following your instructions although i am missing the capacitor you mention. I will look at the diagram posted and see if it mentions what value it is.
Thanks again for opening your set up you,ve been great!