ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: intermittent no sound out the mains unless a large input signal is given  (Read 956 times)

Jeremywhit

  • Newbie
  • *
  • Offline Offline
  • Posts: 2

I am trying to troubleshoot an intermittent problem with an Yamaha emx5000 powered 20 channel mixer. Sometimes after power up, the main speakers will not work unless someone taps on a mic... any mic. The monitors will work just fine and the signal also gets to the headphones. Once you tap on a mic or give the board a large input signal it seems operate just fine. I think it has "shut down" if the board was not used for a while but still powered on. To my knowledge it does not have a noise gate or something along that line (or at least one that a user is able to adjust). Its a fairly basic board.

This is very annoying to say the least to start out the church service with a loud pop, not to mention we are a small church and rely on not so knowledgeable volunteers to help run sound. Please help with any suggestions, I'm not even sure where I can go for repair as we are on a very limited budget.
Logged

David Pedd

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 89
  • Gilbert, AZ

I am trying to troubleshoot an intermittent problem with an Yamaha emx5000 powered 20 channel mixer. Sometimes after power up, the main speakers will not work unless someone taps on a mic... any mic. The monitors will work just fine and the signal also gets to the headphones. Once you tap on a mic or give the board a large input signal it seems operate just fine. I think it has "shut down" if the board was not used for a while but still powered on. To my knowledge it does not have a noise gate or something along that line (or at least one that a user is able to adjust). Its a fairly basic board.

This is very annoying to say the least to start out the church service with a loud pop, not to mention we are a small church and rely on not so knowledgeable volunteers to help run sound. Please help with any suggestions, I'm not even sure where I can go for repair as we are on a very limited budget.

My first question is how old is the board?

My "guess" from looking at the block diagram is that the protective relay is at fault.  Depending on age and use, the contacts could have some corrosion.  If you can open it up, depending on the kind of relay, you could remove the cover and buff the contacts.  Again, just a "guess".
Logged

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16010
  • Hickory, Mississippi, USA
    • Resotune

Perhaps a dirty insert jack, or dirty switch...

JR
Logged
On the internet people tell you everything "they" know, not the answer to "your" question.....  http://circularscience.com/

Mac Kerr

  • Old enough to know better
  • Administrator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6141
  • Audio Plumber

Perhaps a dirty insert jack, or dirty switch...

JR

Or bad solder joint.
Logged

Mike Caldwell

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 929
  • Covington, Ohio
    • Mike Caldwell Audio Productions

That is the classic sign of a slightly oxidized set of contacts somewhere in the signal path. The relay that David mentioned could very well be the problem.

The power amp input jacks most likely have pass through contacts in them, those could be the issue, with it turned off take a plug and insert it a few times in each of those jacks. Better yet get some contact cleaner and a small brush to clean the jack with....power unplugged.

Move the power amp selector switches back and forth a few times.

Are you using the Speakon or 1/4 inch speaker connections
Have you tried cleaning and re seating the speaker cable plugs, even more so if you use the 1/4 jacks.

It could still be a circuit board level problem but my guess is that it's an oxidized contact somewhere.
 

Jeremywhit

  • Newbie
  • *
  • Offline Offline
  • Posts: 2

Thank you very much I will try these suggestions
Logged

David Pedd

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 89
  • Gilbert, AZ

Thank you very much I will try these suggestions

Just make sure to unplug it first!   8)
Logged

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8629
  • Atlanta GA

Maybe there is a gate somewhere.  Either in outboard processing, or DSP etc.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!
Pages: [1]   Go Up
 


Page created in 0.034 seconds with 16 queries.