This is a strange problem om my Madison. anyone?

[wulff]

I bought a 1st generation upd858 Madison Base, I was having problems with the AC/DC switch wouldn't switch to DC as it was the wrong cord, I rewired it so it will run off the built in power supply (I will add a switch later if I want to run off an external DC power). anyway, it was running fine, then I noticed one day last week when I turned it on, there was nothing! I hooked up an external power supply and the meter lights came on as well as the LED's that show what mode you are in.
I rebuilt the power supply and was able to get rid of the external supply and the supply puts out nearly 14 VDC.
But, the problem remains, no TX, no RX, when I put it on SSB the relay chatters so I replaced the famous 2.2uf Tantalum capacitor with a regular 2.2 electrolytic cap paying attention to the plus/minus, no change except the chattering is faster (sounds like a buzzer) on SSB only, still no TX or RX or readout.
Oh, I forgot to mention when I first got it and got it working the 1000uf electrolytic cap where the DC comes into the main board the case of the cap had separated and lifted about 1/4" but it still worked. I replaced it of course but no changes.
I have everything scattered all over the table and my wife wants it picked up before I go in for cancer surgery next Tuesday, I might be able to figure this out myself but the thought of the surgery and my anemia is really making my thinking a bit clouded!
Anyone have any ideas what I am missing?
Thanks
Everyone!

[sonoma]

there is a diode right by the relay that can short out and cause this same problem. look for the diode at the relay and see if it is shorted. should be the only one right at the relay. could also be time to recap the radio since you already found a bad one that was blown. this radio is so old the electro caps are drying out and starting to go bad.

[wulff]

Thanks! I will check that diode tomorrow, (could that have anything to do with the channel readout?) I am recapping it right now, waiting for some caps I have on order. I notice the newer caps are smaller in size even though they are higher voltage, I wasn't aware of changes on the newer caps... sounds good, smaller size but higher voltage, did that have something to do with the 'wet caps' that used to be used?
I never saw a cap case slide up like that one did, I guess the newer ones has the cross-hatch on top to release pressure instead of doing what that one did!
I was going to replace the AM regulator transistor but do you think that would have anything to do with SSB?
I will let you know what the diode change does, by the way I bought a bunch of new Small Signal Schottky diodes (60V 0.015A) I know these wouldn't work for the relay but would they be a good match for any other glass signal diodes, or would you leave those alone?
Thanks again,
Phil

[sonoma]

the diode at the relay is a zenor diode so the ones you have now will not work. you should not need to change any of the receive diodes since they normally do not go bad. if you are talking about the diode receive mod your radio should not need it. it has good receive when working properly already. I have 3 washingtons I recapped 2 years ago that has the 858 PLL in them. the receive is very good on them. the AM regulator does not have any thing to do with SSB. if you get a dead key on AM it should be good. right off the top of my head I can not remember the location of the zenor that goes out by the relay. I had one radio it was shorted and would kill the receive and make the relay act up. that was how I got the one radio for free from the guy that had it. no one could find the problem.
after you recap the radio we can see how it does. on all 3 of mine after a recap I found a few VR's that were bad and would not adjust. that was from the age of the parts.;
hopefully the cap change will help you with some of the problems.

[wulff]

Thanks, I will let you know, I too have heard of VR's that would run out of range so the tech (or whoever was workin' on it) just got it as close as they could and that was close enough.
If I'm not mistaking, I think the Washington/Madison's use quite a few Zenor diodes
Thanks again,
Phil