Connect with us

Pioneer SX-9000 Problems

Discussion in 'Electronic Repair' started by Greg, Aug 22, 2004.

Scroll to continue with content
  1. Greg

    Greg Guest

    Hi,

    I recently came into possession of a 1970 Pioneer SX-9000 receiver.
    While trying it out I found that when changing the volume a loud
    crackling sound was coming out of the speakers. I researched the
    issue and found it was most likely due to dirty contacts, I tried
    some tuner spray but it didn't do anything. I also noticed a hissing
    sound coming out of the speakers when no music was being played and a
    "clunk" noise when turning the unit off. At this point, I contacted a
    local electronics repair shop and took it in for an estimate. They
    gave me an estimate to clean the contacts and replace a few capacitors
    that were bad. Well, I picked up the unit yesterday and 95% of
    cracking is gone and no more clunking happens when powering the unit
    off. However, the hiss remains. In the google archives, I found the
    following:

    http://groups.google.com/groups?q=&rnum=1


    The problems outlined in this post are mostly what is happening to
    mine. The one thing I can add is the hissing gets much worse in one
    channel as the receiver warms up. Within 15 minutes, the hiss becomes
    noticeable and starts to degrade the sound of the music coming out of
    that channel.

    Any suggestions on what I should do to fix this? The above repairs
    already cost me $65 and I don't want to put much more money in to
    this. My electronics skills are minimal (I can solder a bit), so if I
    knew exactly where the problem was I could try to fix it myself.
    Also, do I have a beef with the repair shop?

    Any advice and suggestions would be helpful.

    Thanks,

    Greg
     
  2. Most shops would at least credit the prior repair cost, and charge only a
    modest additional for resolving the problem. Might even charge only the
    additional parts cost. May have a bad transistor or another coupling cap
    could cause this. The link you gave to an SX-1010 would not be directly
    applicable. Totally different model.
    If the problem is appearing consistently, it shouldn't be too difficult for
    an experienced tech armed with a schematic. Without a schem it could get
    dicey.

    Mark Z.
     
  3. Asimov

    Asimov Guest

    "Greg" bravely wrote to "All" (22 Aug 04 09:31:02)
    --- on the heady topic of "Pioneer SX-9000 Problems"

    Gr> From: Greg <>

    Gr> Hi,

    Gr> I recently came into possession of a 1970 Pioneer SX-9000 receiver.
    Gr> While trying it out I found that when changing the volume a loud
    Gr> crackling sound was coming out of the speakers. I researched the
    Gr> issue and found it was most likely due to dirty contacts, I tried
    Gr> some tuner spray but it didn't do anything. I also noticed a hissing
    Gr> sound coming out of the speakers when no music was being played and a
    Gr> "clunk" noise when turning the unit off. At this point, I contacted a
    Gr> local electronics repair shop and took it in for an estimate. They
    Gr> gave me an estimate to clean the contacts and replace a few capacitors
    Gr> that were bad. Well, I picked up the unit yesterday and 95% of
    Gr> cracking is gone and no more clunking happens when powering the unit
    Gr> off. However, the hiss remains. In the google archives, I found the
    Gr> following:

    Gr> http://groups.google.com/groups?q=pioneer+receiver+hiss&hl=en&lr=&ie=UT
    Gr> F-8&selm=d2e5798e.0203062230.7339362e%40posting.google.com&rnum=1

    Gr> The problems outlined in this post are mostly what is happening to
    Gr> mine. The one thing I can add is the hissing gets much worse in one
    Gr> channel as the receiver warms up. Within 15 minutes, the hiss becomes
    Gr> noticeable and starts to degrade the sound of the music coming out of
    Gr> that channel.

    Gr> Any suggestions on what I should do to fix this? The above repairs
    Gr> already cost me $65 and I don't want to put much more money in to
    Gr> this. My electronics skills are minimal (I can solder a bit), so if I
    Gr> knew exactly where the problem was I could try to fix it myself.
    Gr> Also, do I have a beef with the repair shop?

    Gr> Any advice and suggestions would be helpful.

    Gr> Thanks,

    Greg, the shop didn't do a very thorough job but then again this type
    of restoration work isn't very cost effective from their viewpoint, so
    I can't really blame them as it probably cost them more than the $65
    in time alone. I'm afraid a 70's receiver is a nicely complex piece of
    equipment. However, you might try to narrow down the problem as to the
    tuner or the audio circuitry. One question is, does the hiss exist only
    in FM or also in AM or when set to AUX, or when the volume is at zero?

    A+s+i+m+o+v

    .... 'Keep the smoke inside.' -- 1st Rule of Electronics.
     
  4. Brine

    Brine Guest

    Gr> The one thing I can add is the hissing gets much worse in one
    channel as the receiver warms up. Within 15 minutes, the hiss becomes

    The hiss is present regardless of what mode (phono, FM, AM, etc) the
    receiver is in, which set of speaker outputs are used, and whether the
    volume is high or low.

    Thanks,

    Greg
     
  5. Bob Shuman

    Bob Shuman Guest

    Does this receiver have a separate pre-amp to power amplifier output at the
    rear? If so, then check out the signal coming from the pre-amp before it
    enters the power amp by using another units power amp. You can usually feed
    the signals from the pre-amp output to another units AUX input. If the hiss
    is gone, then the problem has been narrowed to the power amp. If the hiss
    remains, then the problem is in the pre-amp. Having a schematic and an
    oscilloscope would help you find the source of the hiss. Since you have one
    good channel and another one that is bad you can compare signals.

    The source of the noise could still be a dirty connector, switch,
    potentiometer, a coupling capacitor as was previously suggested, or even a
    defective filter capacitor or bad ground.

    Good luck.

    Bob
     
  6. jakdedert

    jakdedert Guest

    I believe(?) that this particular one has pre/main jumpers (they would be a
    set of RCA jacks in the back with a piece of wire jumping them together).
    Merely removing those would isolate the problem considerably. If the hiss
    remains with the jumpers pulled, it's definitely in the preamp section.
    Flipping the tape monitor switch 'on' would also isolate part of the preamp.

    jak
     
  7. jakdedert

    jakdedert Guest

    OOPS...make the above 'the power amp section.'
     
  8. Greg

    Greg Guest

    It has outputs marked "pre amp & mixing record". Setting the SX-9000
    on FM, when I run cables from that to my Harmon Karden HK395i
    receiver/amp's tape in I don't hear anything (including hiss).
    However, if I run these same cables from the SX-9000's "Tape A Rec"
    outs to the HK's tape in, I can hear the FM signal (with no hiss).
    Does this mean the pre amp is broken? Would I get any sound out of
    the Pioneer amp if the pre-amp was shot?

    Thanks,

    Greg
     

  9. All it means is the problem isn't in the FM section. The record-out jacks
    are right after the selector switch.

    Mark Z.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-