Separate names with a comma.
Discussion in 'Station & Mobile Pics' started by loosecannon, Jul 28, 2010.
Could share some of he details on your mod light?
Bump for more info, any updates?
hey looky there! some interest in the ol' madison.
I actually do have a pretty big update, and that is that i am going to be selling one of my custom madisons here in the next day or two.
For all the conspiracy theorists out there, it really is just a big coincidence that this thread got revived at this time LOL. i had actually forgotten all about this thread.
I am going to sell the radio here on the forum because i would like it if a forum member got the radio. (it's not going to be cheap LOL)
I will post some pics with the current incarnation and talk about the mods that have been done, but that will have to wait until i get home late tonight.
thanks for the interest!
Just to answer the four year old question about the mod light:
I installed that LED because the radio has an external modulator circuit that bypasses everything in the radio but the driver and final, so there is no indication on the radio that you are modulating.
The circuit is just a simple tap into the collector of the AM modulator transistor that gets rectified to DC in order to light the LED. Can't remember where i found that circuit but its very simple, and only uses a few parts.
Here's one I just finished today
nice madison unit 75.
I noticed you decided to keep the red mode LEDs, or did you go for the red white and blue thing?
how bad was the noise on your freq counter unit?
On this Madison, I went for the red white and blue thing on the mode LEDs. I used a RC series circuit for the counter. Didn't have much noise. Used a coupling cap (39pf) on the TP and the resistor (1k) stabilized the counter reading between the low and high end of the band channels so the end digits wouldn't fluctuate. They are rock solid no matter what channel I'm on. I found you need to fool with the resistance values anywhere from 750 Ohms to 1K Ohms, depending on the radio. I'm almost finished another Madison. I got the red frequency counter with built in VFO from Ralph that I installed. I'm sure you know the one I'm referring to. It has the knob just to the right of the readout. Just recapped the radio last night and I'm going to align it this morning.
Ive installed one of Ralphs kits before, and while he is innovative, the actual board, hardware, and assembly of the kit i found to be not that great.
I had to do a lot of work to the one i did in order to get it to work well.
as for the counter bouncing on band edges, getting your 10.240 crystal right on the money is the best way to keep the counter stable, because it keeps your tripled frequency from drifting up or down at band edges.
of course this chassis didn't come with a variable component in order to accomplish this so you have to replace one of the fixed ceramics with a variable trimmer cap.
I think C86 is the one that gets made variable, but i can't remember which as i didn't have to do that on my madison. its either C85 or C86.
The one thing that always bothered me about ralph's plexi piece is that he didn't paint the back of it black surrounding the counter and you can see inside the radio.
A little bit of painter's tape, and a good cleaning of the plexi before applying some flat black spray paint would have gone a long way toward making it look more factory.
a hint for anyone doing a digital clock madison into a freq counter, you are going to have to remove about a half inch of the factory black paint on the right side in order to have all six digits read out.
hope this is helpful,
LC, Your right on the money about the counter from Ralph. Crap, I spent all day messing with it. Didn't plan for that! I had to remove his VFO and re-do my own using a little daughter board. His worked but it was way too course when you turned it (too touchy and not very practical for a VFO). As far as the plexi, I cut my own. I purchased a myriad of color sheets from a guy in California. The blue plexi on the Madison pic above is an example. You cannot see the internals and no need for paint on the backside. The 10.240 crystal is right on the money. Sorry for the confusion about that. The last digit would bounce around on the higher frequencies ( I believe it was above 27.8450). The radio was stable on the bench counter but not on the retro mounted counter. Any rate, I'm just going to stick with those cheapy eBay counters. They seem to work well. Tomorrow I'm going to do another blue Madison but using the counter with more digits. Will up a pic for you after I finish the re-cap.
Madison #3 Still under construction. Man it's hard to take pictures of BLUE. The camera sensor goes wonky.
I have the better resolution counter in this unit. Oh baby, baby, looks SWEET!! I went with the red white and blue mode LEDS again...cause they are cool. I also installed a 10 turn Burns pot for the clarifier control ( still have to mount the new knob) The radio has brand new 50 and 100v electrolytics installed throughout. ( I know it's overkill but hey). I just now finished the alignment and she is working beautifully! This radio is STOUT !!!