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peavey mixer making a loud buzzing/humming noise

Discussion in 'Accessories / Connections' started by BoomTastic, Apr 5, 2009.

  1. BoomTastic

    BoomTastic Active Member

    Hey guys,

    I uploaded a vid of the mixer and the noise, check it out

    http://www.youtube.com/watch?v=GQZXm8ko9LI

    It was brought from the states to greece and had been in storage for 15 years and only has maybe 3 hours or less of usage. My Dad had it hooked it briefly to a transformer when he first brought it and said it always made the noise.

    So not too long ago we brought to a "specialist" who sets up and fixes stage equipment. He checked the way it was hooked up to the tranformer, made a cable for it and said the noise was normal, and told us everything was good to go.

    Well, the noise...to me....seems to be getting progressively louder, to the point where its annoying now. All the functions on the mixer work perfectly and theres no buzzing background noise coming from the speakers.

    The transformer is big, rated at 2,000 watts. So it doesnt seem to be a transformer issue. Maybe its the fan making the noise?

    thanks for the help
     
  2. MadMax

    MadMax Well-Known Member

    It almost sounds like the fan blade is striking a wire that is in close proximity.

    I'd pop it open and take a quick look around. Look for any wires that could be touching any of the blades of the fan. If you find one, be prepared to replace it, or have it replaced.

    Obviously, you wanna unplug it first... :)

    But, once you get it opened, plug it back in and turn it on if you don't see anything obvious.... then hunt around and see if you can isolate it down a bit further.
     
  3. Davedog

    Davedog Distinguished Member

    Isnt that THE sound of Peavey gear??? :lol: :lol: (I'm Kidding!!)
     
  4. moonbaby

    moonbaby Mmmmmm Well-Known Member

    I thought that was a chainsaw...
    Poor Hartley Peavey. I used to work for him many moons ago, back in the Era of Unpleantness. He used to get SO pissed off when people would make cracks about how his gear sounded... :cool:
     
  5. Davedog

    Davedog Distinguished Member

    I HAVE owned several pieces and for the record...(just in case hes watching these pages) That stuff was indestructable....and all the new stuff I have heard sounds really good....but in the old days there was ZERO tone to any of it.

    Point in fact: A PA I owned was a tri-amped mostly JBL front end with CS800's,CS400's and a 24 chnl MarkIII Board. Anytime you have the mids cranked to 75% with SM57's then there aint no tone.

    Imagine my joy when I scored the PM1000. Imagine my back after hauling that boat anchor around. But there was TONE for days.
     
  6. BobRogers

    BobRogers Well-Known Member

    I have a theory that a lot of musicians hate Peavey gear because they bought it because they could afford it when they were starting out, and then they wanted to get rid of it for something that sounded better, but the damned Peavey stuff never broke down.

    Guys at the local music shops that rent PA equipment to the frat houses cary a lot of Peavey. Drunken frat boy proof.
     
  7. RemyRAD

    RemyRAD Guest

    It sounds to me like the Barings in the fan are shot? So try this? Take a clean and dry plastic drinking straw. Stick it in the back where the noise is coming from in an attempt to briefly stop the fan. If the buzzing ceases when the fan stops, that's the problem. I don't think it's a wire.

    You might even want to vacuum out the entire mixer? Get yourself a soft clean paint brush to dislodge heavy deposits and place the vacuum cleaner hose attachment as close to the dirty areas as possible.

    Maid to order
    Ms. Remy Ann David
     
  8. dvdhawk

    dvdhawk Well-Known Member

    It sounds like audio gremlins are running a sawmill in there. Can you disconnect the fan to eliminate it as a suspect? If you're sure the fan isn't rubbing against something, I'd have to guess some mechanical vibration in the transformer. I had a transformer before that would hum and buzz something like that, and it would get progressively louder as it got warmer.

    Good luck.
     
  9. BoomTastic

    BoomTastic Active Member

    Hey guys thanks for the responses,

    When you lift one of the bottom corners of the mixer, the sound changes and almost goes away, then you set it back down and it returns....

    So it seems its not a transformer or what not. but whats weird is that to me it sounds like the fan, or maybe one of the fans, is on the opposite side of the noise. When i turn it on, it sounds like the fan spins up nicely and quietly.

    So, I took off the handle wood piece/cover on one side and my dad freaked out and said to not touch it and that we would bring it back to the "specialist". :roll: Which is the same guy that said the noise ( not quite as lound back then ) was normal when i asked him about it :roll:

    So, now i have to wait.

    But i will post what the problem/fix is once i the "specialist" figures it out.

    thanks guys
     
  10. Codemonkey

    Codemonkey Well-Known Member

    Admittedly there are probably a lot of wires and components inside a mixer, so...
    I'm kinda against opening ours.

    I think I share your view on "specialists" though. Not always great.
     
  11. MadMax

    MadMax Well-Known Member

    And this is news???? :) :shock: :)




    While there is indeed a potential shock hazard to anyone not at least somewhat familiar with electronics, please forgive me if it sounds like I am (or anyone here) is suggesting you do something that you are not comfortable with.

    But to be honest with you, taking a half dozen, or so, screws out of a cover to at least look inside the unit sounds a bit elemental. As long as the unit is initially unplugged while you remove the screws to gain access to the fan area, you will be plenty safe.

    I'm not suggesting that you completely dis-assemble the unit, just trying to make you aware of how a lot of things work in the world of gear assembly.

    Most of the time there are at least three sets of screws. Often there are more than that, but 3 is the typical number. One for the top components and one for the bottom components and sometimes the rear of a unit... and one set of hardware to hold the thing together.

    Typically, the screws that hold the unit together either hold the top to the bottom, or hold the bottom assembly to the top.What I mean by that is this;
    You will either remove the top of the unit, or you will turn it over and remove the bottom. There are usually two or more sets of wires and/or ribbon cables that tie the two assemblies together.

    Often, there is enough "extra" cable to allow a technician to lift or separate the two units enough to disconnect one from the other. You just don't want to quickly or forcibly yank the two apart. A slow, methodical approach is needed here.... IF you even need to do this step.

    My recollection is that most Peavey stuff from that era is top removal. There will be matching screws that should hold the side plates to the bottom pan assembly AND there should also be a set of screws that hold the rear panel to both the top and the bottom. You should NOT have to remove the 3 side panel screws on the sides to get access to the fan.

    You should be able to use a phillips #2 screwdriver to remove the screws around the perimeter of the back plate.

    Once those are removed, you should be able to tilt out the bottom and swing down the back plate and safely pull it away from the rest of the unit. Once you have access to the fan, you can easily check to see if it is indeed the fan or something else.

    There were a few units that the back plate was actually part of the bottom pan. If that's the case, you would need to remove the entire top assembly to get access.

    Again, I'm not encouraging you to do anything you aren't comfortable with. It's just that IMHO, you should be able to at least open the case and fairly quickly determine if this is an easy fix (e.g. something with the fan) or if it needs to go to a qualified tech service for repair.

    Just remember these simple rules and you will generally always be safe.
    1. Unless the power needs to be on for what you are doing... UNPLUG IT.
    2. Once a unit is open, be sure there are no open liquids near.
    3. Keep your screws organized for easy reassembly.
    4. Make sure that all assemblies are on stable surfaces (floor, table, etc.) BEFORE plugging it in and turning it on.
    5. If you must poke around in the unit when it is turned on, only use non-metalic items.
    6. Always keep one hand in your pocket when poking around an energized circuit.
    7. UNPLUG the unit when you are re-assembling it.

    Hope this helps....
     
  12. Codemonkey

    Codemonkey Well-Known Member

    Definitely helps. Sometimes you forget that lids come off etc.

    My worry is that I won't get the top back on... or pull a cable too far, or ...

    As a learning experience I think I should open it and then put the cover back on, even just to see the inside and blow dust about.

    In a budget mixer, are the knobs/faders typically attached to the surface with cables leading to the electronics on a PCB somewhere, or is the PCB attached usually to the top assembly, or should I just grab a damn screwdriver and find out for myself?
     
  13. BobRogers

    BobRogers Well-Known Member

    Another thing that can be a big help when heading into unfamiliar DIY territory: a digital camera. A sequence of pictures can be a big help in those, "where the heck did this wire go?" situations.

    Update: A safety warning - While Max's advice is great for this mixer and other solid state devices, tube amps have large capacitors that hold charge even when the amp is unplugged. If you are going to be messing with the innards of a tube amp you need to learn how to discharge them.

    Again, for the solid state mixer you are safe from electrical shock if it is unplugged. Just don't extend that theory to tube amps.
     
  14. jg49

    jg49 Well-Known Member

    Ah capacitor discharge! I was working in another room when a tech who was fairly knowledgeable about electronics slipped with a screwdriver and the capacitor discharged completely melting half of the shaft. It sent a ball bearing size piece of metal through the two layered gypsum wall and left a bb size hole in the plate glass window 20' away. Most solid state stuff does have capacitors but they are miniscule in comparison.
     
  15. MadMax

    MadMax Well-Known Member

    Oooo... well, if we're gonna talk about fun stuff.....

    I used to work for a LARGE medical diagnostic imaging company that made cardiac and angio x-ray systems with digital imaging. I worked in the final systems assembly and test area.

    One day a tech was cleaning out his lead lined room after a shipment. He was standing on top of the 480v 3phase 200a feeders and somehow confused the 3 phase knife switch/breaker with a 120v 20a single phase relay disconnect.... don't ask how... no one knows...

    He was ok when he threw the knife... it was when he energized the 3 phase relay that i all went bad....

    It melted his boot soles, melted the steel in the toe into his toes and blew him 30 feet across the room where his body impact broke the 3/4" plywood and the lead lining of the room.

    It dimmed the entire facility and supposedly, the local power grid was calling the facility to find out if the building was still intact.

    The guy spent several hours in surgery while they freed his toes and picked the melted rubber out of his foot. He dislocated his shoulder and fractured either 2 or 3 ribs.

    No capacitors were involved.
     
  16. dvdhawk

    dvdhawk Well-Known Member

    Unfortunately, there are a lot of high-voltage guys who cannot count to ten on their fingers. It only takes a lapse in concentration for a second.
     
  17. Davedog

    Davedog Distinguished Member

    uhhhh.....Well you know what my reaction is gonna be to that story.....

    The SIZE difference in those two disconnects is simply four to one....or maybe a bit more...........


    Ya wants a sparks story?? So be it. Remember, I have been a Journeyman Electrician for about 30 years.....so, been there, done that, seen it done, left the room immediately afterwards....


    I used to do maintainence on oil rigs back in the middle of the country. You drive out to little pumping stations scattered all over the hell of Rural Oklahoma and read the tanks, check the pumps and the motor controllers etc etc.... Its a route. Big 2 1/2 ton work vehicle with a davit to pull those motors..Some weigh a lot....the 25 horse and bigger ones.....The control cabinets are big explosion proof 600 volt monsters and have oil dogg doors on em so if theres a short, the oil cant spew in and ignite....

    Most of these facilities are 600volts. Theres a transformer on a pole and a tap from the 5280 running around out there on the prairie.

    Ok. Heres the story. One day I'm checking a collection tank and theres X amount of oil in it. Everything is working fine. Two weeks later I check it again and theres LESS oil in the tank than the previous check! Hmmmm...Puzzling. I check it on a short week and theres more than before the previous check....Very HMMMM!

    So I decide to get into the controller and see if theres a problem. Its on a stand at the base of the pole holding the transformer about 25 feet from the pumper. OSHA rule.

    Theres a disconnect handle on the side of the controller. I reach for it and the little voice in my head screams DONT TOUCH THAT!!!!!!

    I ALWAYS obey the little voice.

    So I get an 8' piece of 2X4 that we keep on the truck for prying motors off their mounts.

    I wack the handle on the disconnect with it.

    Theres a loud BOOM. I'm dropping and rolling UNDER the truck. The transformer is now at about 2500 feet and burning askarel is spewing down like its the fourth of July.

    The drop from the 5280 is flying around like a big live snake and eventually burns itself through up the bridle from the high voltage away from me and doesnt make contact with the ground.


    Well, this is really exciting.

    The control box, which, like I said is explosion proof and weighs around 300 lbs, is blown open. The front had become shrapnel.

    Long story end....There had been a lightning strike and it had blown the center phase off of its block in the controller and it was simply laying against the box inside. The controller continued to do its thing but every cycle it would single phase itself and run in reverse from the time before. Oil pumps in....oil pumps out.

    Had I touched the handle I would have become one with the angels.

    Always obey the Voice.
     
  18. Codemonkey

    Codemonkey Well-Known Member

    One time, my dad was putting screws back on part of a PC case, the PC was on. He dropped the screw and fried a tiny little capacitor. Nothing bad happened although the temperature sensor never worked again.

    What a boring life I lead.
    Where did I leave that metal fishing line, I'm gonna find me some 11,000V.
     
  19. moonbaby

    moonbaby Mmmmmm Well-Known Member

    Well, when I was a field service tech in the medical imaging biz, I watched a co-worker use a screwdriver as a "probe" while trouble-shooting the power supply of an automated film processing machine.This machine drew a good 30amps, and was serviced by breakers that were in a locked closet . Unfortunately, so were the welders doing construction on a "flyover" corridor that was being built across I-95 to link one hospital building to the other. Well, my pardner let the "probe" slip, and he somehow shorted between the terminals on the primary transformer...POW! Out went the room, the lights, and the welders hanging over I-95. And getting that closet containing the breakers unlocked was going to take a few minutes...
    You could hear the cussing from outside the building. No one was hurt, but I wanted to hide....
     
  20. BoomTastic

    BoomTastic Active Member

    talk about Hijacking a thread! :shock: :lol:

    Still havent taken the mixer to be looked at yet.....

    But i thought of something else:

    The mixer is 60HZ and the transformer is 50HZ...something to do with it?

    With the 50HZ tranformer, i dont think the mixer will ever work perfectly. You see, my father brought all these electronics and home appliances from the states. For instance: The old record player plays the records a tad to slow.....

    Soo, i wonder if the mixer's functions like reverb, digital effects etc are effected like the record player?
     

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