HO says his old tube type radio trips the breaker in his bedroom. Sure enough it’s an AFCI breaker.
Anyone know if there’s something about those old radios that fools an AFCI into thinking there’s a fault? If not, then maybe there’s a loose connection in his antique that actually IS arcing.
What do you guys think?
Replies
Does it have a 2 wire or 3 wire power connection?
If their an external antenna or any other way that anything is connected to it.
AFCI's have a 30 ma leakage trip. They work much like GFCI's for that part, except GFCI's trip at 5 ma.
Those old radio's where very leaky and often the chassis was hot depending on which way it was plugged in.
But there needs to be any other path to ground for it to trip the AFCI.
William the Geezer, the sequel to Billy the Kid - Shoe
Bruce,
One of the first things that go bad in old radios are the capacitors. When restoring an old tube radio, they are the first things to replace. I would bet that possibly one or more of them are internally arcing, possibly setting of the AFCI ? Or, could just be some real dirty contacts in the old mechanical switches. A few shots with some contact cleaner might tell the story ?
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Are these radios worth any thing. I've got one that my son got from a teacher in HS, that was 8 years ago. He's moved out and its sitting in the garage collecting sawdust."Shawdow boxing the appoclipse and wandering the land"
Wier/Barlow
They normally aren't worth too much but some have more value than others.
I have a friend that likes the old tube stuff and he hunts around and buys stuff but he never pays any high amounts of dollars for stuff. He might pay $10 for an old radio and then he normally has to hunt around for the replacements parts.
He has MS and cannot do too many things so his life long love for electrical engineering keeps him occupied. If you don't find a buyer, I'd like to put you in touch with him. He'd love to get his hands on it and play with it (restore it).
Edited 5/30/2009 8:25 am ET by jimAKAblue
Elementary my dear Watson.
90% of vacuum tube devices used a 0.02uF capacitor (sometime larger, but recall mostly 0.02 uF) from one side of the line to chassis for noise reduction.
First hand experience or old age may be needed to know this - my old record player from the late 1940's was well used when a kid, and we often sat on the gravity furnace hot air duct (they were flush with the floor) to be warm.
Depending on which way the plug was in the socket, one always got a tingle when playing a rendition of 'the little engine that could' on 78 rpm (or any record when you touched the arm, we had nothing then except 78s).
Of course now that type leakage current is not allowable via osha, consumer protection, etc....
But, on antique radios or other vacuum tube electronics, current enough to sometimes even trip GFCI, and AFCI are even more sensitive.
Quiz: who can answer what a "hum buster" was????
PS: a gassy tube would 100% set off AFCI, very common failure mode, decade long diffusion of N2 thru seals, typical 600 V plate voltage well above the Paschen minimum.
Edited 5/28/2009 8:53 pm ET by junkhound
A hum bucker in guitar speak is a pair of opposing coils in the magnetic pick up. Most guitar circuts also have a .02 MF Cap ( can't do that lil u easily on this LT, my FN button is gone) in the tone tone control circut to cut the mids a little. Also all ele. is shielded, or else you can pick up the bar cash register ringing up the sales..BTDT, on stage.
For this radio I'd also second your diagnose, and add that the pot(s) are are likely scratchy on the volume side, esp, if the pot is also on/off which I bet it is.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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First off, have him operate the radio while it's placed on a good insulator, with no other attachments (including any external antenna). Have the operator touch only plastic knobs. If it functions OK in that setup then it's internal leakage in the radio. Turning the power plug around the other way may help, especially if it's an AC/DC chassis.
Otherwise, I'd guess that the startup surge when you turn the radio on could look a bit like an arc to the AFCI. Or the main electrolytic filter capacitor may be arcing/leaking internally.
(Note that the old AC/DC units (read the label for "120V AC/DC" if the label is still legible) have the chassis connected to one side of the AC line. Depending on which way the plug is plugged in, the chassis may be "hot". One should never operate these units with missing knobs or any other exposed metal parts.)
Another way to tell if the unit is AC/DC is to peek inside. There will be only one transformer -- the output transformer, and the tubes will start with numbers larger than 6.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
If it is AC/DC it might have a vibrator PS and that could look like arcing enough to trick the AFCI.
I've only seen vibrators in car radios. The "AC/DC" nomenclature was a cover for saying "cheap, and apt to kill you", because it ran straight off the 120V line with no transformer.But I suppose someone somewhere made a table radio once using a vibrator, and yes, that would tend to produce an arc signature. (On the other hand, the implication is that this radio actually works, and vibrators were notoriously failure-prone and it's hard to believe that any are still working.)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Table radio's with vibrators used to be very common.But that was when they did not plug in and use an A battery and B battery.Although there might have been some trasistion models that where basically battery operated with a battery eliminator plug in..
William the Geezer, the sequel to Billy the Kid - Shoe
Thanks, guys for the responses to this odd-ball question. I've forwarded them to the HO.Interesting sidebar to this story. The HO likes tube radio because he says the sound is "smoother" than digitals. His neighbor is a total audiophile who loves vinyl recordings. This guy has a $130,000 record player featuring suspended granite base, 35lb turntable with magnetic "bearings", carbon fiber tone arm and a pickup "that is better than diamond" (what E-VVS1?) I think he said it was a laser pickup that reads the vinyl track without causing any wear and delivers an analog signal. The entire system cost over $500,000."Yeah, but can he take it on the jobsite?", I said.BruceT
> The HO likes tube radio because he says the sound is "smoother" than digitals. I collect old guitar amps. I think they sound more "organic"._________________________________________________http://tinyurl.com/qbdue6
Mike,
My Uncle was in the appliance/electronics business and bought out the entire inventory of tubes from an electronic supplier.When my cousin took over the business he sold tubes on ebay. One tube in particular caught the eye of a guy who rebuilds amps.What he told my cousin was, "how much and how many can I get."Pete
"I collect old guitar amps. I think they sound more "organic""Warmer. I'm looking to get my son an amp fro his acoustic electric and his Les Paul, (90% acoustic though), and was looking at amps last weekend. They had some tube amps in the store and I saw the first amp I ever bought, a Fender Princeton, and about fainted dead away at the price tag.
They wanted over a grand for that little bugger!
I paid $100 for that AND a Supro solid body guitar.Wish I had both of them today.
You ain't lived till ya played thru a Leslie. My dad always had one around for his keys, awesome sound.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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It sounds like your Dad was around during a golden time of amplification & breakthroughs. Your stories about no room on the kitchen table for food because of his repair & doodling with the keys etc have all the makings of a great short story with metaphors scattered everywhere complete with the wild skinny kid pumpin' his bike up that hill with a ...? bass, drum?...what was it? strapped to the back, ever late for his music lessons.They tolerated out of love. I saw it in the eyes of that old man behind the counter, who remembered you when we were having coffee.
Since audiophiles have grabbed this thread, a query for those folks:
Can you or do you know anybody that claims they can tell by ear the difference between a linear and a class D amplifier??
Curious to know what thos exceptional hearing folks hear that they can tell the difference, other than 'it sounds different' ?
A class D amplifier is a pulse-width modulated unit, kind of like a motor speed control. It's highly efficient, and, in theory, can have "linear" response, but frequency response will be capped at about half the chopping frequency. A class A/AB amplifier, on the other hand, generally doesn't have a hard upper limit to frequency response but rolls off gradually.Given a high enough chopping frequency, though, there's no reason that a class D unit can't be made to mimic the response of a highly-linear class A unit. However, it would be a little trickier to mimic the slight distortion of a medium-quality AB unit, and that slight distortion could very well be providing the "color" that is so admired in some units.Also, there is no reason that the frequency/phase response curve of another amp couldn't be mimicked with a class D. It's just a matter of picking the unit you want to mimic and designing the appropriate frequency filter.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Is distilled water the same as spring water?Is a rice burner the same as a hog?In the end, it's all digital because the class A or A/B amp gets mic'd to a PA or recording device, but, yes, you don't have to be a cork sniffer to hear it (or feel it)._________________________________________________http://tinyurl.com/qbdue6
LOL, Yeah, my Ludwig snare drum on the sissy bar of the Stingray...ride that wheelie all the way up that damm Hatfield hill to school.
Dad was aghast that I chose drums over keys, he always said "Drums are NOT a musical instrument" ( Old Pa. Dutchie ya know)
I had to correct him, and say it is the second oldest instrument after the human voice..that shut him up.
Till I started guitar..then THAT was also bad, because "Everybody plays guitar"..he never was a happy man.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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Jer, You really need two amps.
A guitar amp won't be hi-fi enough for acoustic, and an acoustic amp will be too sterile for electric.Another way to go would be a small PA for the acoustic.I'd look on Craigslist for somethin' used. Like cars, the value drops 30-40% as soon as you walk out the door. If you see somethin' you like, you can research it at http://reviews.harmony-central.com/ and maybe avoid gettin' a lemon._________________________________________________http://tinyurl.com/qbdue6
Thanks. I think I just need to do just what you're suggesting, and that is to research it more. I don't know enough about amps and especially acoustic amps that they make these days.
I looked at some Fenders that they had in the acoustic section of the Guitar Ctr here and the guy was showing me how they have a separate input for a good mic which really perked my interest. The sound was really great, but the thing is, you're playing the guitars that are in the store that have been played played & need new strings, they may have a different sound than what you may have at home etc etc. I may have to bring the ax in, but I wanted it to be a surprise.I just have to find out more on what makes an amp an "acoustic" amp. I don't like to drop that kind of $$ 'till I really know what it is.I know he's my kid & all, but I really think he's got a sound (vocal) that is different, warm & really draws people. He gets a hell of a response whenever he plays. He does street singing, & small gigs between classes in Philly. He also makes demos for a songwriter that have gone on to be bought by big names (Dautry (sp?) for one), and the songwriter has offered him a free internship of sorts if he would take time off from college, but his Dad & Mom said that piece of paper from The University comes first.I would like to post some of the studio recordings, but have been told specifically not to.
Anyhow.....back to the amp thing. I will follow your link & keep on searching 'till I feel it's the right one.
Thanks again.
http://cgi.ebay.com/SUPRO-3-4-Scale-Electric-Guitar_W0QQitemZ270399002545QQcmdZViewItemQQptZGuitar?hash=item3ef50957b1&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50
Yup, some serious audiophile money can be spent....
There was a system I liked on display at a high end shop. Just the interconnecting cables were over $100k retail.
Sure sounded good....
Yeah, but those weren't "AC/DC", and generally they were "portable", not table models. Also, they wouldn't normally have used B batteries, since with B batteries supplying the plate voltage there's no need for a vibrator.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
No, the ones that I am thinking of where definite not portables. I am thinking about the 30's when a lot of rural areas weren't electrified. But you are right, if they had a B battery they would not have an inverter..
William the Geezer, the sequel to Billy the Kid - Shoe
Yeah, you're right -- there were those designed to operate off a car battery or a bunch of lantern batteries. I've never really gotten to examine one of those close up.(If one of those is tripping the AFCI then something's REALLY mucked up!)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
"(If one of those is tripping the AFCI then something's REALLY mucked up!)"LOL. Twilight Zone?BruceT