Old Heathkit Transformers and Polychlorinated Biphenyls (PCBs)

Discussion in 'Shock Brother's DIY Amps' started by cometazzi, Aug 3, 2021.

  1. cometazzi

    cometazzi Tele-Afflicted Silver Supporter

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    So about that Heathkit chassis from 1957 that I picked up for a future project:

    [​IMG]

    Pretty cool, huh? I got it for the chassis and the PT, and scrapped the rest. It stunk like ash tray and old oily rags. Concerned about PCBs, I lifted up the transformer to see if it was leaking oil:

    [​IMG]

    As you can see it looked like it had epoxy or bakelite sealing it up. That chunk was already missing out of the center, and since I saw no oil or oil residue, I figured no oil means no PCBs. Right? I also took a screw off the nameplate on the top, stuck a wire deep down into the hole till it bottomed out, and it came out clean. No oil!

    Well, the future project is now. Recently I took the whole thing apart to clean up the chassis. The ashtray smell went away and the oily smell got worse.

    However, looking at the transformer when it's completely free, that's not epoxy nor bakelite. Instead of being hard and brittle, it's thick and squishy. So it's either dried up oil or (more likely) wax:

    [​IMG]

    The Internet says that sometimes transformers were potted in wax (not unlike pickups). Sometimes, the wax contained PCBs, just like the oil did.

    So what's the likelihood that a transformer like this would contain PCB-laced wax?

    I can buy a test kit and find out, but they look spendy. It would be cheaper (and more definitive) just to dispose of this at a local hazardous waste collection site and start over.

    I'm new to all of this but I know a lot of you guys have been round the "Ancient Ebay Parts Chassis" block before. Does anyone know any fast and loose shotgun tests to determine PCB content?

    I can't tell if I'm being over-paranoid or under-paranoid. It's all going to sit out on the porch until I figure out what to do about it though.
     
    Last edited: Aug 3, 2021
  2. wabashslim

    wabashslim Friend of Leo's

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    Don't know about that gunk (be careful), but just thought you'd like to know that I had one of these amps or something similar (didn't build it, just found it), like 40 years ago. I used it to amplify the Sound City preamp I built into a pair of 15" SRO's. Ahhh, memories...

    There, hope that helps!
     
  3. Greg70

    Greg70 Tele-Meister

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    IIRC, PCB's were used in oil-cooled transformers. These were typically large high-voltage units used in electrical substations or railway locomotives.

    EDIT: as I think about it more, I recall that some fluorescent light ballasts also had PCB's in them.
     
  4. Bill Moore

    Bill Moore Tele-Afflicted

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    In the 80's I worker for a power company, when the govt mandated removing PCB oil from all transformers. This after mandating all transformers have PCB oil installed as it was less flammable. The line crew foreman told me everybody there had been covered in PCB's at one time or another while working to get power restored. "All our kids seem to have the correct amount of body parts!"
    I saw a news segment where the fellow that invented PCB transformer oil was asked how he felt about the new laws. He held up a glass of PCB oil and drank it!
    I suspect if one ever encounters small transformers with PCB's the danger is non existent!
     
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  5. Timbresmith1

    Timbresmith1 Tele-Holic

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    You threw away the output transformer? Oof.
     
  6. Jesco

    Jesco TDPRI Member

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    ha! Thomas Midgley, the guy who invented CFCs and putting lead into gasoline, once inhaled lead fumes at a press conference to demonstrate the safety of “ethyl” gas. He had to be hospitalized for lead poisoning immediately after, for the second time.
     
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  7. monkeybanana

    monkeybanana Tele-Holic

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    Yikes, from Wikipedia:

    In 1940, at the age of 51, Midgley contracted poliomyelitis, which left him severely disabled. He devised an elaborate system of ropes and pulleys to lift himself out of bed. In 1944, he became entangled in the device and died of strangulation.
     
  8. cometazzi

    cometazzi Tele-Afflicted Silver Supporter

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    Kinda. I did find the old manual for this and it looked like it would have been a fun kit to put together way back in 1957. I've also got a Heathkit dual-trace scope from the 70s that I bought at a hamfest, already assembled of course. It's a great scope and I get a lot of use out of it, but I wish I could've gotten it in kit form and built it!

    Yeah, they've got a small capacitor in them that contains PCB oil. Ironically, I work for an electronics recycler so we see these often. You think I'd have known better with this transformer :-/

    So was fire retardation the reason for PCBs? If so, I would doubt it would be in this little transformer, as it's pretty low power. I'm hoping that I've lucked out, even if I end up not using it.

    No actually. It came with two- I kept one and gave one to a friend. The OTs were mounted inside the case, so when I saw it on ebay I just thought "chassis and PT!".

    Yeah, that guy was probably smart but definitely negligent. Also from Wikipedia: Poliovirus is usually spread from person to person through infected fecal matter entering the mouth.

    Just sayin'
     
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  9. wabashslim

    wabashslim Friend of Leo's

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    I've got one of those too; it gets used about once a decade but when you need one there's no substitute. Mine was built by students at a now-defunct local tech school. Previously I had a Heathkit single-trace that was very unstable. Looking over the schematic I realized the power supply was designed wrong and the printed circuit followed the errors. I cut a bunch of traces and made a whole new supply that worked better.
     
  10. old wrench

    old wrench Friend of Leo's

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    I wonder how many of the small transformers actually had or have oil in them?

    I know the big ones that drop high power line voltage down are oil-cooled; you can see that their jackets are welded up like a sealed tank.

    It seems pretty impractical to have a sealed construction that's capable of holding oil for a little tranny suitable for a guitar amp.

    It seems like it would be bad news to have your Heathkit stereo amp spring a leak and run oil all over your stereo cabinet and living room carpeting :).

    .
     
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