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SR7400 'protect' problem

Discussion in 'AV Receivers & Amplifiers' started by Kazman, Dec 26, 2004.

  1. Kazman

    Kazman
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    My beloved SR7400 has developed a problem :(

    On all sources it keeps going into protect mode. This only started to happen today, nothing has changed in the setup :( So it is very strange as to why it started to happen now.

    While playing Halo 2 on Xbox Live, whenever someone spoke on the headset forced the SR7400 into protect mode, and since then, it has been happening on all sources :(:(:(:(.

    Anyone got any ideas? I've checked the speakers to make sure there are no shorts, and checked the back of the amp as well.

    I might take it to AV Land tomorrow after giving them a buzz, very strange as to why this is happening. I wanted to watch ROTK:EE today aswell :(:(:(.

    HELP!

    EDIT: It is still under warrenty so shouldnt have any probs getting it repaired/exchanged hopefully. This only happened once before and kinda sorted itself out after a few mins, but now it is happening constantly :(:(:( :confused: :rolleyes: :( :( :(
     
  2. Tejstar

    Tejstar
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    Hmmm, that's strange Kazman. There's no loose wires?

    If not, sounds like something is busted, give AV Land a call and see what they say.
     
  3. Kazman

    Kazman
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    Well, been through the trouble shooting guide, rechecked the wiring, and still nothing obvious. Looks like a fault with the amp, :(:(.

    Good thing AV Land are open tomorrow, will keep everyone posted of the situation, hope this is not evidence of another fault with what is otherwise a fantastic amp.
     
  4. eviljohn2

    eviljohn2
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  5. Kazman

    Kazman
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    Protect mode is where the amp shuts off power to the speakers to protect itself, it comes on for two reasons, 1: not enough power to feed the speakers (unlikely as it never had a problem before), 2: something is either overloading or shorting the system, and the system goes into protect mode to stop it going kaput altogether.

    Hoping AV Land will have a replacement in stock (unlikely as they do not stock it anymore, only the newer SR7500), or hopefully they have a fix. They are not too far from me (about 20mins up the M1), so will take it to them tomorrow, give me a chance to check out the new Panny AE700 PJ too :D and their demo room :).
     
  6. Tejstar

    Tejstar
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    Let us know how you get on :)
     
  7. Roam

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    A bit of a long shot but have you tried resetting the unit? Also I would double/triple check the wiring to see if there isn't any stray strands of wire anywhere. Hope you get it fixed.
     
  8. THC3

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    A cat once ate through one of my speaker wires and low and behold my amp started going into protect mode - first check all of your wires - then get rid of any/all dust bunnies in and around the amp - has power dropped? - added any other appliances to the same line? - anything fall into amp? - what about heat build-up - if all this adds up to 0 then you're gonna need some service!
    Good luck to you........
     
  9. oex

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    you most likely blew a speaker while playing your game. I would disconnect them and test with an ohm meter. if you dont have one then disconnect all but 1 speaker and try it out. connect 1 at a time until you finds the offending speaker(s).
     
  10. godfather05

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    Kazman,

    Got my SR7400 a couple of days ago. Very happy with it so far. I'm using ProAc speakers I friend lend me but wil buy my Quads pretty soon. Still deciding between the 22L or the 12L + subw.

    Hope everyting goes will with your Marantz!
     
  11. Kazman

    Kazman
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    THX, Grinder and oex, thanks for the suggestions guys.

    I've tried the resetting of the amp already, but alas, to no avail. I have rechecked the wiring about five times now, but only at the ends, so will check to make sure our cats haven't chewed through anything :mad:

    oex, your suggestion may hold some light, all the main speakers should easily be able to handle the power dished out from the SR7400, but, I do have some tiny little Elacs as my SBR and SBL channels. When playing in source direct stereo mode, I can play at any volume I like, and everything is fine, so I'm guessing the Quads are ok, will do a full check with the rears and finally the centre.

    Thanks again.

    Godfather, the SR7400 is a great amp, and the Quads work REALLY well with it, if I were you, I'd take the middle road with the 21L's, it is almost the perfect speaker if you have a good subwoofer to back it up :)
     
  12. Kazman

    Kazman
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    Right, disconnected all the speakers from the speaker end, and the amp was still going into protect mode. So rules out the speakers.

    I then disconnected the speakers from the amp end and it stopped going into protect mode, so that kinda rules out the amp.

    Therefore, the only other remaining factor are the speaker cables, just about to check them via connecting them one at a time, oh, the joy of AV troubleshooting.
     
  13. Kazman

    Kazman
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    WOOHOO!! Think I have found the culprit

    The speaker wire to the front right quad appears to be causing it. Strange it didn't occur in pure direct mode though :confused:

    I've checked the amp channel on another speaker with a different cable and it is fine, no protect mode in sight. Going to check the front right speaker with another cable, just to make sure, but seeing that the short took place with the speaker disconnected in my previous test, hopefully it will be fine :) :rolleyes:

    Will get onto it once I've had some lunch :), AV Land were great and gave me some more advice on what to check out. Will report back in a while :)
     
  14. recruit

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    Excellent Fault Finding Kazman :thumbsup:
     
  15. Kazman

    Kazman
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    Well, tested the speaker with another cable, and no protect mode.

    All this hassle over a dodgy cable, but there are no obvious physical signs of it being damaged. Well, looks like I will still be going to AV Land, but only to pick up some speaker cable :):). I'll probably get some matching Van Den Huls, the Silver Anniversary bi-wire cable was what was in place originally.
     
  16. Tejstar

    Tejstar
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    So it was dodgy cable in the end! Glad you've found your fault, at least it puts your mind at rest! :D
     
  17. eviljohn2

    eviljohn2
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  18. Kazman

    Kazman
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    Well, all confirmed now, installed a new cable and everything is fine again :D

    I'm well happy, don't know what I would have done without the amp over the hols!! :eek:

    I checked the dodgy cable up close, and there are no visible marks of damage, no cross strands, very peculiar, anybody else experienced this?

    What is also strange is that the same cable was fine when playing in source/pure direct mode! :confused: Very very odd, anyway, I'm all smiles again :):):) WOOHOO!!
     
  19. Tejstar

    Tejstar
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    Being without an amp over the hols would have been the worst thing :zonked:

    The fact that it works in pure direct mode is very weird. Spooky in fact...
     
  20. godfather05

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    Kazman,

    I'm glad you sorted out your problems.

    I also have another issue with the 22L or 21Ls. Don't have that much space to fit them in and I'm scared that proximity to wall may hinder performance. Thefefore, I feel that the 12Ls with a good subw are a safer option.

    Will keep you posted.

    G.
     
  21. bob1

    bob1
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    What was the cable ,and how long was it?
     
  22. Kazman

    Kazman
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    It was a 3 meter QED Silver Anniversary Bi-Wire bob :) I've kept the cable, and will test it in my back up system at some point, will get to the bottom of it, that cable gave me sterling service for almost 2 years.

    Godfather, the 12L's sound like a good plan mate, same drivers as the 21L and 22L, so the only thing you will lose is a little bottom end, which can be filled with a decent sub as you say.
     
  23. bob1

    bob1
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    The amp obviously didn't like the cable/speaker combination something changed i'm shure the cable can't so it still seems like the amp had a problem to me.
     
  24. Kazman

    Kazman
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    I'm using the same brand of speaker cable that was there before, and no problems now.

    Just as a test, I re-installed the dodgy cable, and it went into protect again. So must be the cable. Nothing changed in the system from when it was working fine, and stopped working. I come down Sunday morning, and the amp just started going into protect mode, very weird.
     
  25. Tejstar

    Tejstar
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    I'd go for the 21L's, they aren't that much more bassy than the 12L's and are approximately a similar price once stands are accounted for.
     

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