Solid State Amp Slow to Start

Discussion in 'General Electronics Chat' started by treyiii, Aug 23, 2013.

  1. treyiii

    Thread Starter New Member

    Aug 23, 2013
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    I have an older (1989) ElectoVoice power amplifier that is slow to start. By that I mean it powers on into protect mode and stays there for sometimes 5 minutes before it operates normally. It is a solid state amp, and I am not even sure how to describe this problem so I can do more research on the cause. Does this sound familiar to anyone?
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Five minutes is unusual. Even my old tube amp warms up far faster than that.
    No idea about what's wrong.

    Well, I suppose it's watching for a voltage on a capacitor somewhere, and maybe you have a bad cap that's barely making it.

    That's just wild speculation.
     
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Or higher than normal resistance up stream feeding into it?
     
  4. #12

    Expert

    Nov 30, 2010
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    While we're wildly speculating, maybe 24 years is long enough to wait between checking the filter capacitors. (What wayneh said.)
     
  5. treyiii

    Thread Starter New Member

    Aug 23, 2013
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    It is getting up there in years. I guess I have been spoiled by having amps from the late 60s and 70s that fire right up and have never been touched. This one may have had a rougher life.
     
  6. #12

    Expert

    Nov 30, 2010
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    It's OK. I have one from 1978 that's still working.
     
  7. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Sticky relay contact.
     
  8. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Dried out electros making too much ripple. As they warm up they start to come good (ripple reduces) so the protect circuit will eventually click the amp on.

    You can point a hair dryer at the caps and narrow it down to the filter cap (or area).
     
  9. treyiii

    Thread Starter New Member

    Aug 23, 2013
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    After a year of trying to figure out this problem, That did the trick pointed the hairdryer at different areas of the board and instantly saw a result. Now I will just change the capacitors and everything should be working great. Thanks for everyone's help. Sorry the solution was so simple.
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Congrats on finding the cap(s).

    If you plan to do a lot of electronic repair, you should consider buying an in-circuit ESR meter. You just touch that on the cap legs on the PCB (no need to remove the cap) and it tells you if the cap is bad or has started to go bad.

    With practice you can go right over the PSU electros in a couple of minutes, before you even need to turn the soldering iron on. It can also tell you if new caps in your junkbox have started to go bad from age.
     
  11. wayneh

    Expert

    Sep 9, 2010
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    Are you kidding? We love those around here! Come on back when you get it working and let us know. We also love success stories.
     
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