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My incredible 771

Discussion in 'Exclusively Sansui' started by RMS 330, Sep 15, 2018.

  1. RMS 330

    RMS 330 Member

    Messages:
    69
    I posted my recent experience in this thread.
    http://audiokarma.org/forums/index.php?threads/some-sansui-praise.836968/#post-11964198
    I have never owned a Sansui till a couple days ago ($75 CL). I cannot believe the incredible sound I hear. Soo sweet to my ears. I am told this is just the way Sansui receivers sound. If so I will be a Technics convert.
    My new/old 771 looks great, but has some problems I am hoping some of you can help me clear up.
    There is a low hum thru the speakers with volume off as well as some speratic popping noises (occasionally loud ones). The popping also can happen during normal playing volume. I have only used a TT so far. The tuner section does not function but I rarely use that anyhow.
    I do not want to use better speakers or use it at all until I know what the underlying problem is.
    I am no technician, but hope resolve the issues in house. I will open it up and post some pics. Any thoughts would be greatly appreciated.
    IMG_20180914_230014.jpg IMG_20180914_230200.jpg IMG_20180914_230223.jpg
     
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  2. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,717
    Location:
    Fort Dodge, Iowa
    Looks sharp..
     
  3. RMS 330

    RMS 330 Member

    Messages:
    69
    IMG_20180915_223106.jpg Not sure what 4 ch adapter means
    IMG_20180915_223125.jpg IMG_20180915_223238(1).jpg IMG_20180915_221715.jpg IMG_20180915_221731.jpg IMG_20180915_221748.jpg IMG_20180915_221804.jpg IMG_20180915_222021.jpg
     

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  4. sansui 74

    sansui 74 Active Member

    Messages:
    115
    Location:
    Seattle Wash
    Your 771 my be in need of a recap, lots of helpful people here. Ken
     
  5. RMS 330

    RMS 330 Member

    Messages:
    69
    Found this in another thread. Will do this first.

    When I first got my 771 it hummed. Cleaning the connector on the Driver Board (F-1499A) solved the problem for me.

    I had the problem as described by others in this thread: A fairly loud hum when the unit was powered on - present regardless of volume, selector setting, thru speakers or headphones - steady hum and nothing would affect it. I pulled the F-1499 driver board and used Deoxit on the blue connector. Re-assembled and the unit is as quiet as it could possibly be.
     
  6. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    290
    Location:
    Everett, WA
    Love my 881 that the usual suspects walked me through fixing. It's on the bench getting relamped now and I need to have a new face glass cut while it's apart.

    My newly found KR-7600 might be close, I need to do a proper A/B when I get time.
     

     

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  7. RMS 330

    RMS 330 Member

    Messages:
    69
    IMG_20180915_222021.jpg
    Is this the F-1499 driver board?
     
  8. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    290
    Location:
    Everett, WA
    That's your driver board, the part number will be on it.
     
  9. RMS 330

    RMS 330 Member

    Messages:
    69
    Thanx Milo.
     
  10. jdwk

    jdwk AK Subscriber Subscriber

    Messages:
    3,371
    Location:
    Bowie MD
    I have heard that receiver, and it is a real sleeper. Receiver guys never mention it, but if the secret gets out it will get expensive.
     
  11. Soundphile

    Soundphile Active Member

    Messages:
    211
    Location:
    Kuala Lumpur, Malaysia
    The random popping noises could well point to failing small value transistors. And together with a good recap job and calibration, this will be a definite keeper.
     

     

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  12. jcpcali

    jcpcali New Member

    Messages:
    5
    Location:
    West San Fernando Valley
    Hey congrats on the 771. I also picked one up a year ago and love it, which brings me to a question. If this isnt the proper forum please point me in the right direction. In addition to the 771 I also have a qrx 7001. I have an opportunity to pick up klh model 20s, which I believe are 4 ohm. Im a zero when it comes to impedence matching. Can I use these 20s with bith the 771 and 7001. I have some large advents Id like to pair with for the quad pissibly but most likely with the 771. I’m getting into vintage after raising my kids and focussing on their interests (video games). I have a bunch of tube consoles in various stages if restoration, also a fusher 500c in need of recap. Im a daily lurker simply because whatever I google there has always been existing info posted. I love this site and appreciate all of the knowledge you experts share.
     
  13. RMS 330

    RMS 330 Member

    Messages:
    69
    The KLH 20s are 4ohm. You can only run 1 set of speakers at 4 or 2 sets at 8ohms or better. I'll be trying a pair of 20's on mine as soon as I;m sure the poppjng is gone. I think they will be a complimentary match.
     
  14. RMS 330

    RMS 330 Member

    Messages:
    69
    I removed the driver board, cleaned it and the blue connector. Also gave it the full deoxit treatment. I let it dry for 3 days before firing it up. And guess what?
    Complete Silence> No discernible hum. Not a single pop. So I hooked up the TT and it sounds Beautiful.
    Now the pops I was getting were similar to the little pops you hear from a dirty record but louder at 0 volume. Some times alot louder, Like I thought the wife banged on the ceiling during a George Thorogood song with a broomstick loud.
    I only listened for a half hour. But will give it a good 2 album test when I get a chance. I'll post results after.
     
  15. RMS 330

    RMS 330 Member

    Messages:
    69
    I am so grateful for all the extremely helpful people here. I recently figured out (I think) what this term means as I see it alot: "Re"placing "Cap"acitors?
    I'm sure I will need to learn how to do this at some point, but am glad I didn't need to yet.

    It was not expensive, was easy to tune up to max efficiency and sounds awesome. Doesn't matter to me how much someone else is willing to pay for it, cause This One Is Going Nowhere.

    It's a keeper. I managed to eliminate the audio deficiencies with a thorough cleaning. That will be my first step with any receiver I get going forward. My limited tech capabilities require the simplest solution possible.

    The testing: Hooked up 3 pair of speakers. KLH 20, Pioneer CS-G203 and Allegro 2000 In a 12x16 room. Allowed it to warm up for a half hour, no volume and switched thru all functions. No hum or pops.
    Put on an album and tried all speaker outputs, sounded good. Volume at 2, had that wow, warm feeling again and finished the lp. At 3 with a cd in and BAM, that Incredible sound is even better. Finished the cd. Now confident all is well, time to turn up the volume. Got to 4 and it literally chased me from the room. Left it at 4 and went about my various projects thru out the house only going back to switch speaker/component combos and music. Did this for a solid 5/6 hours. Could not be more impressed. It is now my main source for listening pleasure.
    Now its on to the FM section which does not work. No sound at all. Any suggestions on where to start troubleshooting?
     
  16. summitradio

    summitradio New Member

    Messages:
    8
    Please get the service manual there is one here... https://www.hifiengine.com/manual_library/sansui/771.shtml I'd start by looking at the connectors to the f 1479 board (tuner board) as they may be corroded and not getting power. also clean the selector switch with de-ox-it as they get black with gunk. Enjoy!
     
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  17. Rotoflex4

    Rotoflex4 Active Member

    Messages:
    134
    I may be stating the obvious, but if the FM muting is ON (especially if no antenna is hooked up), it can seem like the FM is not working when in fact nothing is wrong. Had me baffled for a while on my 661.
     

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