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metzman
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Post subject: "Dreaded" Silver Mica Disease? Posted: Jun Wed 11, 2008 1:44 am |
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Joined: Nov Wed 14, 2007 11:37 pm Posts: 740
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Why does everyone call it "Dreaded"? I thought it was pretty fun repairing IF cans. Sure, it takes time and patience, but its far from impossible to fix. There are other things that I dread more, like "dreaded mouse pee syndrome" or "dreaded broken dial glass, where am I gonna find another one illness" I'm sure there are others. Why is silver mica disease the only thing referred to as "dreaded"?
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Mr. Detrola
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Post subject: Posted: Jun Wed 11, 2008 2:01 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 18137 Location: Detroit, MI USA
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While some are comfortable with doing that repair, it seems that many find it beyond their ability or understanding even though pretty clear photos of the procedure are available. The problem really becomes "dreaded" if you have an AM-FM set with 5 or more IF transformers, all needing to be rebuilt.
I agree there are worse problems, and that rebuilding IF transformers becomes much easier the more of them one has done. Radios with mouse damage or broken glass are better passed over for nicer examples, unless they are extremely rare models.
_________________ Dennis
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Dave Doughty
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Post subject: Posted: Jun Wed 11, 2008 12:03 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 13650 Location: Utica, NY 13502 (USA)
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I just call it "dreaded" only because everyone else does. Actually, I believe the term "dreaded IF transformer silver-mica migration disease" was coined here by someone here at ARF and it just seemed to stick. It does seem like a dreaded plague that is so common among the legions AA-5 sets that exist.
Dave
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HuggyBear
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Post subject: Posted: Jun Wed 11, 2008 12:18 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 6804 Location: Warren, MI, USA 48093-6744 N42.50973 W83.02633
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I refer to the rubber covered wiring problem as "dreaded". I've only had one radio that I had to rework the IF cans on (Hammarlund HQ-100A boat anchor), but I've had lots of radios with rubber wire rot.
_________________ The mind is like a parachute - just because you lost yours doesn't mean you can borrow mine.
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VT 52
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Post subject: Posted: Jun Wed 11, 2008 2:01 pm |
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Joined: Jun Thu 08, 2006 9:52 pm Posts: 686 Location: Lake Lavon, Texas
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As it does not qualify as a true disease, and it is hardly a scourge of mankind, then could it be one with a wry sense of humor that coined it.
If you are not aware of the condition, and spend hours chasing your tail trying to get that gremlin out of the signal path, only to find its something this simple ,you apply comic relief, and give it a name that brings a smile, after you fix the problem.
My most feared and dreaded disease is the out of cash to by more radios disease.
Rick
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jim campbell
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Post subject: Posted: Jun Wed 11, 2008 6:06 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 1189 Location: Knoxville TN
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If IF transformer migrating silver mica caps bring on an intermittent problem, noise, ect then I would "dread" it for sure. Components that are missing or broken are easily recognized as such. Intermittents give me a fit.
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greg mercurio
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Post subject: Posted: Jun Wed 11, 2008 9:33 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 1024 Location: New York City
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I think we call it dreaded because we electronically upgrade a radio's electronics and clean up the body then, we give it a test run.
Oh no! We hear the radio play with that staticy sound. Don't bother testing anything else. You know what it is!
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OZ132HOME
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Post subject: Posted: Nov Wed 24, 2010 2:31 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 4817 Location: La Porte, IN, USA
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You guys that find it fun to rebuild IF cans should consider setting up shop and doing bunches for sale. Those of us with 8 tube Zeniths needing to have all or several replaced would buy some--for a fair price...
Better than installing NOS miller Ktrans that will do the same thing in a few years...
_________________ Apolitical and Agnostic Forever (Well, on the Forum, anyway)! -OZ
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Burnt Fingers
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Post subject: Posted: Nov Wed 24, 2010 3:07 pm |
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Joined: Oct Sat 20, 2007 3:36 am Posts: 13596 Location: New Hampshire
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What Ive found with 50's AM-FM Zeniths is not SMD but voltage puncture of the dielectric. These are in decent size cans that come apart easy and repair is quick and painless.
The puncture is the dark spot in the very top in the photo below.
Now when you get to the 3/4" cans and a bunch of them in something like a Hammarlund HQ-170 or 180 then it becomes dreaded as its a slow process. Its not a task for a fumble fingers without good tools.
Carl

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JohnOBrien
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Post subject: Posted: Nov Wed 24, 2010 5:20 pm |
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Joined: Jul Fri 13, 2007 1:48 am Posts: 2038 Location: Washington DC
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OZ132HOME wrote: You guys that find it fun to rebuild IF cans should consider setting up shop and doing bunches for sale. Those of us with 8 tube Zeniths needing to have all or several replaced would buy some--for a fair price... Better than installing NOS miller Ktrans that will do the same thing in a few years...
Hear Hear! Yes those that find rebuilding IF transformers "easy" should put their money where their mouth is and offer rebuild as a service.

_________________ John O.
"Apolitical and staying that way"
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terrydec
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Post subject: Posted: Nov Wed 24, 2010 5:51 pm |
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Joined: Oct Sat 31, 2009 6:53 pm Posts: 3630 Location: Louisville, Ky
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I've repaired a couple of cans. You need the schematic, the EXACT replacement caps and good alignment equipment.
I wonder why it's called "Dreaded SILVER mica disease. There's no silver, just aluminum, mica and a brass rivet.
I don't think I would ever 'shotgun' all of the cans in an AM/FM receiver, just the bad ones. I've had radios that have two different types of IF cans. Usually only one would go bad.
Starting a "Dreaded silver mica disease" fix-it shop isn't such a bad idea. Probably not very profitable though.
Terry
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BigBandsMan
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Post subject: Posted: Nov Wed 24, 2010 6:41 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 6032 Location: Raleigh NC USA
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There's only one condition that I truly dread about any gear I ever have to work on.
And that's the condition of "everybody-and-his-brother-got-in-there-first!"
Grrrrr!
L
_________________ It don't make a go if it ain't got that GLOW!
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JohnOBrien
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Post subject: Posted: Nov Wed 24, 2010 6:53 pm |
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Joined: Jul Fri 13, 2007 1:48 am Posts: 2038 Location: Washington DC
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BigBandsMan wrote: There's only one condition that I truly dread about any gear I ever have to work on. And that's the condition of "everybody-and-his-brother-got-in-there-first!" Grrrrr!  L
That is truly worse than SMD and epidemic.
_________________ John O.
"Apolitical and staying that way"
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terrydec
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Post subject: Posted: Nov Wed 24, 2010 6:55 pm |
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Joined: Oct Sat 31, 2009 6:53 pm Posts: 3630 Location: Louisville, Ky
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I've had some repairs where the previous tech was a total goober. I had one that took me weeks because I had to use the schematic to practically rebuild it.
I don't know about anyone else, and I'm not trying to hijack this thread, just make a comment; but when ever I fix a set, I try and use what I see to envision the last tech who worked on it.
Was he sloppy and just slapping some stuff in to get paid, or was he the type who took his time and made an effort to do a good job, no matter the monetary reward?
I can usually tell. I can see this older guy taking a sip of coffee, or setting down his cigarette, maybe his eyesight is like mine and he has to put on his 'reading ' glasses. He carefully picks the right part and uses his 200 watt iron to solder it in.
My grandfather was like that, and so was my dad. And I try my best to emulate them.
Terry
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Brian McAllister
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Post subject: Posted: Nov Wed 24, 2010 8:00 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 2555 Location: Sarasota FL USA
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I always thought that it was derived from "the dreaded Lurgi (or Lurgy)" which was from an episode of the BBC Radio comedy show of the 1950s-1960s "The Goon Show", and made its way into the language in many English-speaking areas.
dreaded lurgy noun
[S] UK informal
a humorous way of speaking of any illness which is not very serious but is easily caught
_________________ Brian McAllister Sarasota FL http://oldtech.net
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BigBandsMan
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Post subject: Posted: Nov Wed 24, 2010 10:52 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 6032 Location: Raleigh NC USA
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Sounds like our "blue flu."
Very common among certain people at work, anywhere, anytime.
Especially the friends of friends.
L
_________________ It don't make a go if it ain't got that GLOW!
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Lou deGonzague
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Post subject: Posted: Nov Thu 25, 2010 1:00 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 6980 Location: Latham NY
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My hat's off to you Metzman. you enjoy working on old radios and find it challenging and rewarding and that's what it's all about. Sure some jobs are easier but what fun is that if you just slap a few caps in and it works perfect 
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Pbpix
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Post subject: Posted: Nov Thu 25, 2010 1:11 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 9155 Location: Haledon, NJ, usa
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metzman wrote: Why does everyone call it "Dreaded"? I thought it was pretty fun repairing IF cans. Sure, it takes time and patience, but its far from impossible to fix. There are other things that I dread more, like "dreaded mouse pee syndrome" or "dreaded broken dial glass, where am I gonna find another one illness" I'm sure there are others. Why is silver mica disease the only thing referred to as "dreaded"?
I've never understood the apparent aversion to mouse pee or turds by most ARFers here.
So many guys here, it seems, complain about it when a radio shows up with it.
So what? No biggie.
A quick whisk out and a wipe down solves it.
So what's the big deal?
Whenever I ever had to handle "yuckie" stuff like baby diaper drippings or kid puke or cat or dog "gifts"... I just stop and remember what my mother told me many years ago when I was a boy. She reminded me it's not a big deal by saying :
"That's what they make soap and water for".
_________________ " To be a man, Be a non-conformist, Nothing is as sacred as integrity of your own mind." Emerson
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Jack Shirley
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Post subject: Posted: Nov Thu 25, 2010 1:42 am |
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Joined: Mar Fri 14, 2008 1:40 pm Posts: 8407 Location: SE USA
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Pbpix wrote: I've never understood the apparent aversion to mouse pee or turds by most ARFers here.
So many guys here, it seems, complain about it when a radio shows up with it. So what? No biggie. A quick whisk out and a wipe down solves it.
So what's the big deal?
Apart from having very corrosive effects one also has to think about hanta-virus carried by mouse pee....even old dried-out mouse pee.
All this stuff about cadmium, asbestos pads, selenium, solder fumes, pcb, etc is no reason to wear a haz-mat suit when working on an old radio but folks new to the hobby should be made aware that these things exist so that reasonable measures are taken to minimize exposure to anything that might be remotely dangerous. That's not worry-warting...its just common sense like 'don't stick your hand in a flame'.
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Dave Doughty
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Post subject: Posted: Nov Thu 25, 2010 1:54 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 13650 Location: Utica, NY 13502 (USA)
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terrydec wrote: I wonder why it's called "Dreaded SILVER mica disease. There's no silver, just aluminum, mica and a brass rivet.
SILVER is deposited on one side of the mica sheets to form the plates of the cap. You can see the silver deposits in Carl's picture. It is not aluminum.
Dave
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