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What is wrong with this pic - Number IV

Discussion in 'Question of the Day' started by Mayhem, Dec 26, 2004.

  1. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    I hope that everyone had a good holiday and that your minds are nice a clear. Now, the following picture was taken when I was asked to service an Amplifier. Now this is a home amp, not a professional PA one. However, I have seen a few professional ones in a similar condition.

    [​IMG]

    Here are the things that I would like you to consider:

    What is the problem?
    What can this problem cause? and how
    What can be done to prevent the problem?

    Think about the amps that your school/theatre/church have and where they are located.
     
  2. avkid

    avkid Not a New User Fight Leukemia

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    that looks to be covered in pet hair and dust , to stop the problem:cover when not in use and clean occasionally!
     
  3. soundman

    soundman Well-Known Member

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    I secound dust and would suggest puting a filter infront of the intake fan/grate. Also might consider moving the amps from the bottom rack space to a bit higher because then they wont suck in so much crud of the ground.
     
  4. great_beyond

    great_beyond Member

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    the problem is that dust has covered everything, causing:
    - insulate everything and over heat it (fire)
    - buildup a static charge and destroy the circuits (fire)

    First thing would be to clean everything, then to prevent it, place a couple pieces of cheescloth over the intake fan, and other holes for ventalation, and cover when not in use,
     
  5. ccfan213

    ccfan213 Active Member

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    it looks to me like dust or possibly sawdust, i had a similar issue in my house where my dad started building computers in the workshop in our basement, naturallly there is sawdust everywhere and it screws up electronics and is very flammable. first off you should not keep an amp in a room where there is sawdust, but other than that i agree with what other people have posted about covering and putting screens in vents
     
  6. zac850

    zac850 Well-Known Member

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    It looks like sawdust that is covering it. This is bad because things can short out, destroying the amp and possibly causing a fire.
     
  7. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Ok - everyone is right in so far that the circuit boards are covered with dust. However, dust in itself is not conductive.

    great_beyond is heading down the right track with the potential problems that dust can cause but there is a bit more to it.

    avkid - as for cleaning the amp, how often is occasionally?
     
  8. soundman

    soundman Well-Known Member

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    your right its more like an insulater which can cause a problem to with heat. Also it can gum up fan bearings cause them to fail which is not good. Depending on where the amps are used I would clean quaterly if not more. Taking it out of the rack opening it up and blowing it out w/ air dosnt take that long.
     
  9. Peter

    Peter Well-Known Member

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    I really really hope the strands of stuff in there is not asbestos! Probably abit less likely to be found in a house, but people with racks in other buildings might have to keep an eye out for it abit more.

    asbestos is BAD news, it's harmless when it's not in the air, but it has a tendency to become airborne and get stuck in people's lungs and cause VERY serious medical problems.

    It is really a fairly wild guess, but hey, cant hurt to toss it out there can it?

    (JBTW, I will be gone out of town for a week, and i hope to see lots of posts here by the time i get back! See ya all later!)
     
  10. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Nope - not asbestos. The fibres are actually spider webs.

    Now we are getting off track here. The composition of the dust is not important. All you need to know is that it is dust. Now, think about what problems dust on electrical circuit boards can cause.
     
  11. Ex-Techie

    Ex-Techie Member

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    Besides being an insulator which increase operating temps, dust can also be a conductor which can cause both hard and intermittent shorts, e.g. failures and or noise in sound gear. Moreover, contaminates combined with moisture can become corrosive. Note, this is much bigger problem with newer state of the art electronics versus older through-hole technologies. The new chips have much tighter lead to lead spacing (pitch) and the possibility of shorts is greater.
     
  12. Radman

    Radman Well-Known Member

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    I see the problem:

    Made in Japan!

    No I'm kidding....
     
  13. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Ok – well Ex-Techie has started to link things together. Dust, whilst being an insulator can cause overheating through holding heat close to the components, it is not conductive when dry.

    However, add a little moisture to the equation and you do have a very nice conductive medium. Now we all know that liquids and electronic components do not mix, nothing new here but most just think that by preventing people drinking near, or placing a drink in the immediate vicinity is enough to remove this risk.

    This is not the case. Part of this question was to get you to link the whole dust + moisture = risk scenario as being a serious problem. When stating that you should think about your own theatre environment, I wanted you to think about the possible sources of moisture.

    Another thing was to get you thinking about equipment maintenance (and why it is important). There was some discussion about covering air vents but I would not tend to do this. Keep in mind that some amps have fans that force air into the amp, some have fans that draw air out of the amp and some have both.

    Now, I am not actually going to elaborate on these points now. Rather, I am going to leave them open for discussion. Part of being a responsible tech is being able to look at an issue and then identify what the possible problems that can arise and why. Once you start thinking in this way, you will find that risk reduction becomes much simpler. Remember, you are much better asking “would this cause a problem” than asking “Gee, I wonder why that happened”. Initially though, looking at past problems will put the little red flags into your mind, which (hopefully) will pop up when you see similar things later on.

    So – the challenge is still there – cite the possible sources of moisture that are commonly seen in the industry and give the basics of cleaning amps and keeping them clean.

    I look forward to reading the discussions.
     
  14. soundman

    soundman Well-Known Member

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    Beer, water and summer gigs where it is 110% hummidity and will rain if just given a chance. Most amp racks either are used to support the moniter desk or have NO DRINKS wrote on them using gaff tape.
     
  15. mbenonis

    mbenonis Wireless Guy Administrator Premium Member

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    One possible source of moisture would be improper HVAC settings for the room/facility. It could also be caused by leaving doors open (expecially in a humid climate) if the rack is near an exterior door. Solution: make sure all doors stay shut and that the building is kept relatively dry.
     
  16. ccfan213

    ccfan213 Active Member

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    you can install a dehumidifier in the room where you have your amps, and of course keep liquids away from it. also put the amps high in the rack so if there is flooding or a spill of some kind they are less likely to get wet.
     
  17. JahJahwarrior

    JahJahwarrior Active Member

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    thinking of our amps and dimmer packs...and man, i actually thought that dust would hold in moisture and was so excited and then i read mayhems' post......drat. oh well!

    causes of moisture: i live in florida and we had many hurricanes this year.
    outdoor gigs, or an amp that is kept outdoors, tha would be a very fine candiate for dew from moisture! also, if you have an amp in a cold room, then turn the heat on, you will get some condensation inside. you have to keep that in mind in the winter. drinks are always a problem but you konw when that gets in there, it's the moisture in the air that you can't tell about. how to protect: 1) keep your amps in a dry place, up in the air, i mean in a well ventilated spot, where ther eis lots of air around it. 2) in the winter, keep the heat on so the amp doesn't get freezing cold, set it for like 60 or so. and don't warm it up to toasty warm too fast. 3) in the summer don't let it get really hot then stick it in the ac really fast. don't ever leave amps in hot sun. (I'm thinking more portable amps or racks here) 4) if your room gets really wet, say you have a leak in the cieling and the humidity is super thick, buy a dehumidifier and run it for a while, close to your amp.
     
  18. thelightguy

    thelightguy Member

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    It is helpful to have a fehumidifyer in the room, as this not only eliminates moisture, but mold.
     
  19. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Ok - we seem to be a little stuck on this one.

    So far we have correctly identified the thick layer of dust as being a problem for the following reasons:
    :arrowr: insulator – reduces the heat exchange which can lead to damaged components
    :arrowr: fire hazard – a large amount of dust could catch on fire, sparking a larger fire once other combustible materials catch alight.
    :arrowr: Shorting – once the dust becomes moist, it can conduct electricity, leading to shorts and arcing between tracks and components.

    You have also recommended cleaning your amps and covering them up.

    This is all good work. However, there is one very common cause (the most common) of moisture in the entertainment industry that has not yet been identified. I’ll give you a hint:

    It is something that many of you use and several post have been made on this site regarding their use. When combined with dust, the end product is a nice sticky moist conductive medium.

    The other thing that I would like to see explored in a bit more detail is the process of cleaning an amplifier. Who can give me a basic step-by-step breakdown of what to do. Just a few lines on each point is all I need. Something similar to the dot points I used above.
     
  20. soundman

    soundman Well-Known Member

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    aghh fog/haze
     

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