Help: EV RE20 Repair

Discussion in 'Recording Studio' started by kfowler8, Feb 13, 2017.

  1. kfowler8

    kfowler8 Senior Member

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    I mentioned this last week that I had a chance to pick up an EV RE20 mic for cheap. I knew the mic had an internal rattle.

    I disassembled the mic this weekend and it looks like it's the common problem where the black disk becomes unglued from the diaphragm. I can see the disk moving around.

    [​IMG]

    I've seen a couple of threads on the internet about fixing this. It appears to be a little tricky. There's a decent post HERE on a fix the guy did.

    My question is I'm unclear on how to actually get at it. He talks about de-soldering the magnet wires and removing the magnet. Here's some pic of the side. Any idea of how to go about this?

    [​IMG]

    [​IMG]

    Thanks for your help. Let me know if the pics don't show.
     
  2. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    You could always give the masters a call first.

    Never know, they might offer a replacement capsule.

    What you are looking to do is very tricky by itself, but it looks like everything is soldered together to boot!

    If this is a known issue, they may offer a fix.

    That is a pro series mic after all, not a USB weekender special.




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    Another alternative. Could be cheaper.

    check out www.micdaddy.com as they do RE-20 repairs starting at $109
     
  3. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Found this guy on another forum, but it might be worth shooting him an e-mail.

    Says he used to work for EV.


    Regarding 'baby rattle syndrome':

    There are 2 types that I see as a common mode failure.

    -the first is when the foam supports have failed or start to crumble. This allows the element to freely bounce around inside the case. Not a good thing.

    -the second is when the pole piece under the diaphragm comes free from the alnico magnet it was previously adhered to. What happens is that the plastic disc bounces around within the voice coil underneath of the diaphragm. It translates as distortions and buzzing on fast transients and high SPL sources ie kick and bass. On normal speaking and voice applications it's quite possible it goes unnoticed until the microphone is 'handled' and a slight plastic 'clicky' sound is heard.

    It's possible to refurbish the microphone suffering either problem.

    If you'd like to discuss in more detail feel free to drop an email

    ben@micdaddy.com

    I am the former service tech for electro-voice microphones.

    I am a true DIY'er at heart and an active member at groupdiy if you would like to tackle your mic and I can give any advice please shoot over an email.

    BTW the set screw in the top/front grille at the address end is 0.035" hex. I get asked this a lot [​IMG]
     
  4. kfowler8

    kfowler8 Senior Member

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    Thanks Darrell. I was going to call EV later today and ask if they had any guidance on this. Supposedly it's like $250 to send the mic back to them to repair. I wonder if they'll sell me just the element?

    I saw that post from Ben. I was considering that. I also saw some posts from back in 2014 where people were complaining because he was not responding to emails after they had paid. Sounds like he got overwhelmed.

    I'd really like trying to fix it myself.
     
  5. kfowler8

    kfowler8 Senior Member

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    Spoke to EV technical support and repair. They were pretty useless. They don't have any literature on doing the repair. Couldn't even find out what glue to use. It was obvious the tech guy had no idea what he was talking about.

    Repair said it's more expensive to buy the element then to send it in for repair. How does that make sense? $230 for the repair. That would be a $380 all in cost for me. Definitely a last resort.
     
  6. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Yes, but not unheard of in this throw away age.....

    Like you, I try to fix everything myself, as much as I am able.

    Years of inferior work (to my standards and against what was promised anyway), plain getting nowhere, and I hate waiting and spending money on stupid stuff that shouldn't have broke in the first place!

    Ok Rant over.

    Take more pics, from more angles, light it up good in the crevices, lets see what its made of.
     
  7. kfowler8

    kfowler8 Senior Member

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    Made some great progress tonight. I got the diaphragm removed from the element. Talk about tricky! I think everything is intact. Got ready to glue the disk back on and realized I didn't have the right glue. Bah! So close to being done.

    I've been taking lots of pics so I'm going to start a new thread with a step by step of what I did. Seems a lot of people are looking for details on fixing this.
     
  8. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    did you go through the top by removing the diaphragm?

    Some have said cut the glue around edge.

    That seems a little nerve racking and you've got to not damage the voice coil AND get it re-aligned in center!

    Good luck. What a crappy design! If you're going to put something under there at least screw, pin, glue it down!
     
  9. kfowler8

    kfowler8 Senior Member

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    It's a horrible design. Especially for a decent mic. I can't believe they couldn't find a better way to secure this.

    I used my solder sucker to remove most of the solder where the magnet wire touches each post. Hard thing is they also glued the wire down. I basically melted that away with the solder iron.

    I couldn't find exactly where they soldered the wire to the post. Fortunately there's some slack available. So I ended up cutting the wire right at the post. I've got plenty left to re-attached. I then score the edge of the metal place with a scalpel. There's glue on it too. Next I put a large flat head screwdriver on each side of the metal plate. There's a big spot on each side that's ideal for this. I then turn the driver 90's on each side. It lifted the metal disk pretty easily. I was actually surprised how easy it came off. Problem is the magnet wants to pull it back down. That's where you have to be careful.

    Picking up some glue today. Not sure what to use yet. Was thinking 5 or 30 min epoxy.
     
  10. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    If the underside of the plastic if smooth you can always rough it up a little or notch it with a sharp knife to give the glue more holding area.

    But with a good sticky epoxy it shouldn't need it.

    You don't need liquid steel or anything with filler in it. two part clear will probably work.

    Not a lot of weight to hold down should be more than enough surface area.

    Don't overdo it! Epoxy is good strong stuff, you DON'T want it oozing out from under and catching the diaphragm or voice coil.

    With the head assembly still apart see if you can clamp it down in a vise or small 'c' clamp while it's drying.

    As a thought you could use construction adhesive to glue the frame back together.

    It hardens to a similar goop to what you took off, and can be heated or cut loose again in the future.

    Do NOT epoxy that mess together or you will NEVER repeat this operation.

    My 2Cents. Not even enough for a cup of coffee!
     
  11. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Dang! I need pics! :shock:

    I wish I was there and could watch. This sounds like FUN! :thumb:
     
  12. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Just read the other thread you have about epoxy.

    IMHO JB weld is the stuff I was suggesting you avoid in this case.

    It does fill metal and that's what it is designed for.

    But you don't need it in this application, and you don't have any SPACE in there for filler.

    More filler=less glue. This is like the opposite of head repair on an engine.

    This is like Nero-surgery. There is no room in there to begin with.

    Any filler underneath will raise the disk up slightly and depending on the design, may cause the diaphragm to strike against it during loud transients.

    Go with the clear, two part.

    Don't squeeze it directly onto the magnet.

    Mix it in a bottle cap first till evenly mixed and cloudy.

    put a dab on a toothpick and drop it in the center of the magnet.

    Apply dome and clamp.

    Go find something to do for the rest of the day.

    my 2 cents
     
  13. kfowler8

    kfowler8 Senior Member

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    Thanks Darrell. I get what you're saying. I've got a bunch of detailed pics I'll post. You'll get a kick out of em.
     
  14. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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  15. kfowler8

    kfowler8 Senior Member

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    Just got off the phone with EV again. Guy was actually very helpful and knowledgeable. He said they've changed the design to address this problem but they used a type of epoxy resin back in the day.
     
  16. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    That red stuff on the xlr jack is red rtv silicon sealer.

    It's the butyl rubber kind, not pure silicone. Used to seal HVAC exhaust piping and camper roofs on the old popups.

    Just there to keep the moisture out, but if you want to do it right, might as well re-seal it.

    Didn't want to interrupt your 'how to post', so I thought I'd drop my 'helpful hints' in here.
     
  17. kfowler8

    kfowler8 Senior Member

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    Got it. Made the correction. Feel free to add any corrections there. Thanks!
     
  18. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    I would, but I don't want to dilute the continuity of your progress. :)

    I fear that if I say something that someone else might refute or add to, then it becomes a distraction from the technical nature of your 'how to' thread.

    I'd rather hash it out on the sidelines. But if you think it would be of value, I will defer to your wishes, it's your thread.... :thumb:
     
  19. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    BTW if anyone asks why they stick that stupid disk under there in the first place it looks to me like it's there as a bumper for the diaghram.

    Think kick drum.

    If something loud wails on that thing and drives it down hard, the diaphram cone falls onto the disk and is stopped before it bottoms hard against the magnet.

    This would quickly lead to fatigue of the voice coil area and eventual tearing and separating of the voice coil from the diaphragm.

    Seems to me a little felt dot would have done the same thing....

    still should have been center drilled into the magnet face and a little plastic pin on the disk, would have solved everything.
     
  20. kfowler8

    kfowler8 Senior Member

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    Yeah, sees like a really bad design. Makes sense on the purpose.
     

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