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    Weber copper cap discoloring?

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    wgallupe

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    Weber copper cap discoloring?

    Post by wgallupe on Sat Oct 11, 2014 12:33 pm

    Hi, question to the group: Is it normal for the Webber rectifier to discolor? The copper color has faded (from heat I assume) leaving a mostly silver/grey appearance. I should add that I did remove the blue label and hand buffed it with fine steel wool before I installed it. I'm thinking this is a non issue but...confused

    ps: the amp sounds great. No operational issues other than the discoloration.
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    Bob Latino
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    Re: Weber copper cap discoloring?

    Post by Bob Latino on Sat Oct 11, 2014 1:18 pm

    Yes .. In time the Weber Copper Cap will turn a silver/grey color whether you buff it or not. Copper oxidizes over time .. If this bothers you, then you can just buff it up with some metal polish ..

    NOTE - The reason Weber makes this rectifier out of copper is because copper dissipates heat very well. Once or twice a year I get an Email from someone asking why the Weber Copper Cap "gets so hot". There is a lot of current passing through this rectifier and it does get hot .. This is normal ..

    Bob
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sat Oct 11, 2014 1:46 pm

    wgallupe,
    If your Webers start giving you electronic grief, tmadden on this board has created an excellent fix for them that will cool them down.
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    wgallupe

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    Re: Weber copper cap discoloring?

    Post by wgallupe on Sat Oct 11, 2014 2:50 pm

    Bob, Thanks for the quick reply. I feel better now.

    Deepee, Thanks for the tip. How will I know if/when I need that mod?

    Enjoying some great music with the help of my ST-120 on a cold and rainy Saturday afternoon in Massachusetts....

    Dale Stevens

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    Re: Weber copper cap discoloring?

    Post by Dale Stevens on Sat Oct 11, 2014 3:47 pm

    deepee99, wgallupe; what mod?? Dale
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sat Oct 11, 2014 6:52 pm

    Dale Stevens wrote:deepee99, wgallupe; what mod??   Dale

    Tmadden mods them with a bit of cooling and a beefier thyristor or thermistor, best just to ask him.
    I sent him a handful of ones I'd blown and he fixed them; I'm still on the first pair he sent back. A craftsman, to be sure.
    The Webers get VERY hot with a low-impedance speaker load, that's why I was blowing them. I've since rectified (pardon the pun) that problem as well, but it's good to have some confidence in the Webers now that I did not have before.
    I would just give Troy a PM for details. I'm a dunderhead at this stuff.
    Cheerio
    d


    ramon68

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    Re: Weber copper cap discoloring?

    Post by ramon68 on Sat Oct 11, 2014 7:55 pm

    I hope tmadden's Weber Copper Cap mod gets put up in the "Sticky" section.
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sat Oct 11, 2014 8:04 pm

    ramon68 wrote:I hope tmadden's Weber Copper Cap mod gets put up in the "Sticky" section.

    Agree. He can fix broken ones, which I'd been tossing into the dust-bin. The Webers have a heat problem that can be fixed.

    Guest
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    Re: Weber copper cap discoloring?

    Post by Guest on Sat Oct 11, 2014 11:47 pm

    ramon68 wrote:I hope tmadden's Weber Copper Cap mod gets put up in the "Sticky" section.

    ditto on that, Mr Madden, if you could please put up a sticky on this, we'd all appreciate it, thanks!
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    arledgsc

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    Re: Weber copper cap discoloring?

    Post by arledgsc on Sun Oct 12, 2014 12:00 pm

    The Webers are pretty neat but having the power resistor inside the can with the rectifying diodes doesn't seem like the best way to go for long-term reliability.  Makes for a nice, neat package but I'm still shaking my head as how long can it last before it blows.  

    I have a spare Weber but have been wondering how to open the Weber copper cap for repair.  Anyone know? But I would definitely like to hear more about tmaddens mods.
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sun Oct 12, 2014 12:15 pm

    arledgsc wrote:The Webers are pretty neat but having the power resistor inside the can with the rectifying diodes doesn't seem like the best way to go for long-term reliability.  Makes for a nice, neat package but I'm still shaking my head as how long can it last before it blows.  

    I have a spare Weber but have been wondering how to open the Weber copper cap for repair.  Anyone know?   But I would definitely like to hear more about tmaddens mods.

    I don't want to expose any of Troy's trade secrets as I was sort of his guinea pig, but basically it involves drilling some strategic ventilation holes in the case, and beefing up one of the internal parts. There's a lot of heat build-up in that little can and nowhere for it to go, exacerbated by its proximity (on the M-125 at least) to the xformers.

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    TMadden

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    Re: Weber copper cap discoloring?

    Post by TMadden on Sun Oct 12, 2014 1:04 pm

    Hey everyone, this is what I did to David's Weber rectifiers. I drilled 4 evenly spaced holes towards the top and bottom of the copper case to let some of the heat escape. Most of them had shorted diodes, I replaced them with 1N4007's. Several of the thermistors had completely "burned up", I replaced them with Ametherm Inrush Current Limiters, Mouser P/N 995-SL12-12102. I glad to hear David is having good luck with them!
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sun Oct 12, 2014 1:09 pm

    Yep I am. I would highly recommend Troy's mods to these things. IMHO they'll last as long or longer than NOS Mullard GZ-33s (2-3k hours) and perform just as well. Not as pretty to look at as the tube rectumfriers, but they do the job. So don't throw your burned-out Webers away, send 'em to Troy. Never had any but the best help from him.
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    TMadden

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    Re: Weber copper cap discoloring?

    Post by TMadden on Sun Oct 12, 2014 3:46 pm

    This may be another  solution to keep the Webers cool. I haven't tried one, but it looks like it should fit.
    It's made by Pearl.

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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sun Oct 12, 2014 5:06 pm

    I like the cooling holes better. That's real ventilation.
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    Pillo69

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    Re: Weber copper cap discoloring?

    Post by Pillo69 on Mon Oct 13, 2014 5:38 pm

    Copper can be cleaned with flux to be used in plumbing for welds.
    Put on the tube and then rub with a cotton cloth. If the patches are too deep one has to heat the flux to copper until the dough begins to bubble.



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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Mon Oct 13, 2014 7:22 pm

    Philo,
    One of those pictures would not pass movie PG ratings.
    There's also Brasso, and Noxon if you can find it.

    DarthBubba

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    Re: Weber copper cap discoloring?

    Post by DarthBubba on Wed Jun 24, 2015 11:57 am

    deepee99 wrote:Philo,
    One of those pictures would not pass movie  PG ratings.
    There's also Brasso, and Noxon if you can find it.

    Try catsup (Ketchup) or vinegar.  Likely household items, non-toxic, and very effective for cleaning copper.  Very Happy

    NOT for use on TMadden modified Webers, however.  No
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Wed Jun 24, 2015 12:58 pm

    DarthBubba wrote:
    deepee99 wrote:Philo,
    One of those pictures would not pass movie  PG ratings.
    There's also Brasso, and Noxon if you can find it.

    Try catsup (Ketchup) or vinegar.  Likely household items, non-toxic, and very effective for cleaning copper.  Very Happy

    NOT for use on TMadden modified Webers, however.  No

    Actually, I wouldn't sweat the discolouration. The Webers are there in the back, yes, copper will get some heat treatment over time, doesn't affect their performance.

    jmczaja

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    Re: Weber copper cap discoloring?

    Post by jmczaja on Sun Feb 19, 2017 3:24 pm

    I'd like to ventilate my Weber copper caps TMadden style.. What kind of glue is used to reattach the copper to the base?

    Thanks!

    -jay
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Sun Feb 19, 2017 3:48 pm

    I would think Loctite hi-temp, or one of these:
    http://www.cotronics.com/vo/cotr/ea_electricalresistant.htm
    I wouldn't go overboard; you just want something that in case you bump it, it doesn't cause the loose cap to touch any of the innards. If the thing goes pear-shaped a second time, junk it. Means that one of the diodes is likely shot.
    As I said, I only use my antique GZ-33s for visiting royalty. Otherwise perfectly happy for the less expensive Webers, or Gold Lion GZ-34s if you want the tube look/sound.
    Enjoy the glue fumes; just make sure they're not flammable.

    jmczaja

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    Re: Weber copper cap discoloring?

    Post by jmczaja on Sun Feb 19, 2017 5:39 pm

    Thanks! The diodes should be easy enough to replace if they were to go bad.. Great information here!

    Jim McShane

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    Re: Weber copper cap discoloring?

    Post by Jim McShane on Mon Feb 20, 2017 5:16 pm

    TMadden wrote:Hey everyone, this is what I did to David's Weber rectifiers. I drilled 4 evenly spaced holes towards the top and bottom of the copper case to let some of the heat escape. Most of them had shorted diodes, I replaced them with 1N4007's.

    Nicely done!

    Might I suggest you use the UF4007 diode instead of the 1N4007? The UF series are the same physical size, etc., but they are much quieter than the 1N series. And in my experience it is a nice improvement for just a few cents per diode.

    Dogstar

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    Re: Weber copper cap discoloring?

    Post by Dogstar on Mon Feb 20, 2017 8:06 pm

    The Webber SS rectifier I used for over 2 years showed no sign of discoloration. I'm wondering if by using some sort of abrasive and polish perhaps removed the clear coat that may have been on the copper housing that may have protected it from discoloration? Just a guess.
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    deepee99

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    Re: Weber copper cap discoloring?

    Post by deepee99 on Mon Feb 20, 2017 8:30 pm

    TMadden wrote:This may be another  solution to keep the Webers cool. I haven't tried one, but it looks like it should fit.
    It's made by Pearl.

    Problem with those is, they're almost as expensive as the tubes themselves!

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