Hi all,
Well, after completing the analog madison project, and spending a lot of time enjoying it; i began to get the bug to do a digital clock madison project.
Since my last project involved modding pretty much every section of the radio, including bypassing the audio sections pretty much completely; i decided it would be neat to have a Madison that was essentially stock as far as the audio and RF sections are concerned.
the only mods to the radio besides the addition of the freq. counter are that i added schottky diodes to the noise blanker section (i always do this), I made the AMC variable (they are not variable in stock form of a madison), and i upped a couple values of the electrolytic caps when i re-capped the radio for improved power supply filtering.
I started with one of these chinese frequency counters that are available for about 10 bucks on ebay:
It's size is pretty much perfect for the two screw holes that are left behind when you remove the digital clock module.
You just need to make a couple of small metal brackets that will provide a hole on either side of the actual three digit LED banks. the two holes in those barrel nuts are 3/4" apart, so if you have some small metal blanks, just drill three holes for each one, with the holes being 3/8" on center.
The barrel nuts that come with the counter boards are two long, and need to be replaced with barrel nuts that are half their lengths. this will push the actual LED displays further forward in the radio providing a better look.
sorry i don't have pics with the faceplate off, i got too excited to see it completed and screwed the faceplate on LOL. I will remove it and take a few pics to add in to this thread.
You need to use metal to make your brackets, and here's why:
The multiplexing noise these counters create is pretty severe, and you can hear it in your receive all the time.
By tying the PC board ground to the chassis ground at every point in the radio where i could, adding a shield to the back of the counter board, and filtering the DC in to the board with a 3300uF cap (seen on the back of the shield), i was able to knock this noise down to where it's barely audible, and can't be heard behind normal empty channel static.
here is a pic of the back:
In that pic you can see the shield, the electrolytic, and the wires that i ran to one of the tatile switches on the front, so i can turn the counter off if i want.
since the barrel nuts on the counter board are connected to its PC board ground plane, and it is mounted using metal parts, there is no actual ground wire going to the counter board.
that black wire you see coming off of the power plug on the board is just going to the electrolytic cap.
I believe this had a great effect in lowering the noise.
OK, here is a pic of the finished product:
yes, i left the stock bulbs in the meter lights for a more vintage look. Here is a pic using a flash:
Now for the caveat, since there will always be at least one when doing a project like this.
If you choose to do this to your madison, you are going to find that even though the counter board fits pretty much perfectly into place, the actual display window in the faceplate isn't wide enough, and will cover the last half of the "hundreds" digit. (the zero on the right).
You will have to carefully tape off the top and bottom of the magenta window on the back of the faceplate, and use a solvent to remove some of the black 'paint' on the right side. about 1/4" should do it.
Be sure to use a solvent like mineral spirits that won't fade the magenta window material that is under the black paint. thank goodness they used a large enough piece of magenta film at the factory!
The radio and counter work flawlessly! and it is a real joy to operate. I have to say that the sound of a JFET modded silver eagle D104 with a stock madison set right at 100% modulation sounds really good and this is probably going to be my main radio for this year.
The only other thing i am planning on doing to this radio is to add a Channel King board, once i can get back in touch with the creator of those boards.
I can't wait to use all those cool silver tactile switches on the front of the radio for all the functions of the channel king boards.
aaaaand one more pic for good measure!
this was a fun build, but it's not as simple as just slapping the thing in there.
it definitely takes some finesse and a little custom work.
hope you all enjoy!
LC
Well, after completing the analog madison project, and spending a lot of time enjoying it; i began to get the bug to do a digital clock madison project.
Since my last project involved modding pretty much every section of the radio, including bypassing the audio sections pretty much completely; i decided it would be neat to have a Madison that was essentially stock as far as the audio and RF sections are concerned.
the only mods to the radio besides the addition of the freq. counter are that i added schottky diodes to the noise blanker section (i always do this), I made the AMC variable (they are not variable in stock form of a madison), and i upped a couple values of the electrolytic caps when i re-capped the radio for improved power supply filtering.
I started with one of these chinese frequency counters that are available for about 10 bucks on ebay:
It's size is pretty much perfect for the two screw holes that are left behind when you remove the digital clock module.
You just need to make a couple of small metal brackets that will provide a hole on either side of the actual three digit LED banks. the two holes in those barrel nuts are 3/4" apart, so if you have some small metal blanks, just drill three holes for each one, with the holes being 3/8" on center.
The barrel nuts that come with the counter boards are two long, and need to be replaced with barrel nuts that are half their lengths. this will push the actual LED displays further forward in the radio providing a better look.
sorry i don't have pics with the faceplate off, i got too excited to see it completed and screwed the faceplate on LOL. I will remove it and take a few pics to add in to this thread.
You need to use metal to make your brackets, and here's why:
The multiplexing noise these counters create is pretty severe, and you can hear it in your receive all the time.
By tying the PC board ground to the chassis ground at every point in the radio where i could, adding a shield to the back of the counter board, and filtering the DC in to the board with a 3300uF cap (seen on the back of the shield), i was able to knock this noise down to where it's barely audible, and can't be heard behind normal empty channel static.
here is a pic of the back:
In that pic you can see the shield, the electrolytic, and the wires that i ran to one of the tatile switches on the front, so i can turn the counter off if i want.
since the barrel nuts on the counter board are connected to its PC board ground plane, and it is mounted using metal parts, there is no actual ground wire going to the counter board.
that black wire you see coming off of the power plug on the board is just going to the electrolytic cap.
I believe this had a great effect in lowering the noise.
OK, here is a pic of the finished product:
yes, i left the stock bulbs in the meter lights for a more vintage look. Here is a pic using a flash:
Now for the caveat, since there will always be at least one when doing a project like this.
If you choose to do this to your madison, you are going to find that even though the counter board fits pretty much perfectly into place, the actual display window in the faceplate isn't wide enough, and will cover the last half of the "hundreds" digit. (the zero on the right).
You will have to carefully tape off the top and bottom of the magenta window on the back of the faceplate, and use a solvent to remove some of the black 'paint' on the right side. about 1/4" should do it.
Be sure to use a solvent like mineral spirits that won't fade the magenta window material that is under the black paint. thank goodness they used a large enough piece of magenta film at the factory!
The radio and counter work flawlessly! and it is a real joy to operate. I have to say that the sound of a JFET modded silver eagle D104 with a stock madison set right at 100% modulation sounds really good and this is probably going to be my main radio for this year.
The only other thing i am planning on doing to this radio is to add a Channel King board, once i can get back in touch with the creator of those boards.
I can't wait to use all those cool silver tactile switches on the front of the radio for all the functions of the channel king boards.
aaaaand one more pic for good measure!
this was a fun build, but it's not as simple as just slapping the thing in there.
it definitely takes some finesse and a little custom work.
hope you all enjoy!
LC
