Hello people.
So I got this President Madison from a person who only knew that it light up and so on.
I thought to myself,excellent for learning purposes. In worst case I could take out all the parts,make it nice and pretty and put another radio in it.
I could post pictures of the inside if its wanted,but to start off with some of the info I know. It does transmit in Am/Fm mode and it worked fine. However,there is a annoying talkback on Am. If I remember correctly its not on Fm. When I first time opened this radio,right away I looked for the added Fm-board .. As I`m no expert I wanted to run it through here and see if its correct. The board was labeled Pc 743 AA.. I might be wrong,but looking at pictures of other madisons I could not remember seeing that board on those,but its still just a guess. So any info on this would be at great help. Could it have come from a lets say Zachary T80 which is AM/FM ?
There is another little tiny board labeled PC 645 AA,which has some crystals on it. I just assume this is what gives the radio the 40 extra channels on what I think used to be channel 9 switch. ?
One thing that I know does not work as it should is the Squelch. And the problem is hard to describe.
I first thought it was the knob,so I sprayed it with something similar to "deoxit" (is it?) to make it smooth,because frankly most of the knobs felt like they needed that,both in my ears and my fingers. That did not work. On Am,Usb and Lsb its almost as if some squelch is on,because the sound does not change as I can hear when switching mode.
On Fm on the other hand its the right sound,noisy easy to spot Fm-sound.. So I turn the squelch a little.. noise gone,but so is the person that was talking. As if its on full squelch right away.. ok. So I figure,this knob might be faulty,lets check if I can change it. I try with a potentiometer that has same value 100kb ,but not the PA switch in the start..I`m not planing to use that so I`m fine with it,I connect the two cords that turns radio into CB and not PA mode,and starting up. No change. Fm has the clear Fm noise,and when turning the knob it goes way to silent,with a 10-20 % turn. As before.
My first guess now is that at least the Fm-squelch is gone wrong,but I`m only guessing that when I track down the wires from squelch knob some would go to the board "Pc 743 AA" ..I might have seen at least one of the wires go there,but am still early on in my attempt to understand this highly modified radio. I also noticed that whoever modified it also made "Swr Cal" control power output. It does not have more than 4w am/fm and 7-8w ssb.
BTW,one question I did ask myself,but still has not checked is:
Could someone have tried to make a sort of automatic squelch,or maybe a more correct term would be a "higher minimal setting" with a resistor somewhere,or am I way of?
These PA-switched squelch knobs apparently has 9 spots. Where is the wires suppose to go,and most important is one of them suppose to go to one of the 4 mic pins? Or can that be a part of the home-made talk back thing?
Any advices,ideas or comments would be highly appreciated.
I will post updates as soon as I have them. And please give me questions if needed,I would check whatever asked as quick as I can and report back here with any findings. Just remember I am learning as I go here..
Thanks for reading.
So I got this President Madison from a person who only knew that it light up and so on.
I thought to myself,excellent for learning purposes. In worst case I could take out all the parts,make it nice and pretty and put another radio in it.
I could post pictures of the inside if its wanted,but to start off with some of the info I know. It does transmit in Am/Fm mode and it worked fine. However,there is a annoying talkback on Am. If I remember correctly its not on Fm. When I first time opened this radio,right away I looked for the added Fm-board .. As I`m no expert I wanted to run it through here and see if its correct. The board was labeled Pc 743 AA.. I might be wrong,but looking at pictures of other madisons I could not remember seeing that board on those,but its still just a guess. So any info on this would be at great help. Could it have come from a lets say Zachary T80 which is AM/FM ?
There is another little tiny board labeled PC 645 AA,which has some crystals on it. I just assume this is what gives the radio the 40 extra channels on what I think used to be channel 9 switch. ?
One thing that I know does not work as it should is the Squelch. And the problem is hard to describe.
I first thought it was the knob,so I sprayed it with something similar to "deoxit" (is it?) to make it smooth,because frankly most of the knobs felt like they needed that,both in my ears and my fingers. That did not work. On Am,Usb and Lsb its almost as if some squelch is on,because the sound does not change as I can hear when switching mode.
On Fm on the other hand its the right sound,noisy easy to spot Fm-sound.. So I turn the squelch a little.. noise gone,but so is the person that was talking. As if its on full squelch right away.. ok. So I figure,this knob might be faulty,lets check if I can change it. I try with a potentiometer that has same value 100kb ,but not the PA switch in the start..I`m not planing to use that so I`m fine with it,I connect the two cords that turns radio into CB and not PA mode,and starting up. No change. Fm has the clear Fm noise,and when turning the knob it goes way to silent,with a 10-20 % turn. As before.
My first guess now is that at least the Fm-squelch is gone wrong,but I`m only guessing that when I track down the wires from squelch knob some would go to the board "Pc 743 AA" ..I might have seen at least one of the wires go there,but am still early on in my attempt to understand this highly modified radio. I also noticed that whoever modified it also made "Swr Cal" control power output. It does not have more than 4w am/fm and 7-8w ssb.
BTW,one question I did ask myself,but still has not checked is:
Could someone have tried to make a sort of automatic squelch,or maybe a more correct term would be a "higher minimal setting" with a resistor somewhere,or am I way of?
These PA-switched squelch knobs apparently has 9 spots. Where is the wires suppose to go,and most important is one of them suppose to go to one of the 4 mic pins? Or can that be a part of the home-made talk back thing?
Any advices,ideas or comments would be highly appreciated.
I will post updates as soon as I have them. And please give me questions if needed,I would check whatever asked as quick as I can and report back here with any findings. Just remember I am learning as I go here..
Thanks for reading.
