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Restoring a 1972 Sansui 310

Discussion in 'Exclusively Sansui' started by Thierry, Jun 14, 2007.

  1. Thierry

    Thierry Tape with a passion

    Messages:
    554
    Location:
    Paris, France
    Hi all,

    I am new to this board and I would like to get tips or tricks from you guys the Sansui specialists :thmbsp:

    I am in the process of restoring a nice little Sansui 310 and I have put my work so far on a web page : http://www.dcx2496.fr/sansui310.php

    Does anyone know existence of a maintenance manual or diagrams to help me checking testpoints voltage values ? I have checked the offset on the loudspeaker terminals, seems to be a bit high at 150mV. Now I'd like to set the bias - if it's possible, maybe it's an automatic setting, don't know yet.

    The receiver seems to be working nicely though, but I'd like to learn a bit more about it.

    Sorry for the page in french but I think the pictures speak for themselves.

    Thanks

    Thierry
     

     

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  2. Stene

    Stene The Introducer

    Messages:
    2,200
    Location:
    Stockholm Sweden
    Voltage 44VDC (collector of power transistor)
    Bias 15mA (Remove Quick Acting Fuse and put your DMM in place. Adjust VR803/VR804)
     
  3. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    11,484
    Location:
    Long Beach, CA
    Hi Thierry. The little 310 looked very dirty. You have become an expert at cleaning electronics. This site lists the 210 manual but I don't see a 310 manual listed. Try contacting them to see if they have it.

    - Pete
     
  4. Thierry

    Thierry Tape with a passion

    Messages:
    554
    Location:
    Paris, France
    Thanks ! This is what I figured out after removing the fuses. I found 44,30Volts

    Thierry
     
  5. Thierry

    Thierry Tape with a passion

    Messages:
    554
    Location:
    Paris, France
    Thank you for the input.

    This afternoon I managed to minimise a lot the hiss in the FM section by adjusting some variable capacitors and chokes. I now have a perfectly silent reception.

    I also aligned the display of the tuning index according to the frequency of a Studer reference tuner. Index is now spot on.

    Only problems left is are the following :

    • stereo indicator doesn't light as I have mono reception only. Before you ask : bulb is functionning, I tested it.
    • signal strength indicator is not working in FM, although it works in AM. Weird.

    I'll post more pictures tonight, I have cleaned the cabinet and the faceplate. They look brand new ! This little thing sounds incredibly well for a 35 years old electronics. They knew what they were doing at Sansui :yes:

    Cheers

    Thierry
     
  6. Thierry

    Thierry Tape with a passion

    Messages:
    554
    Location:
    Paris, France
    Hi again,

    I adjusted the bias current, one channel was largeley off specifications with 33mA. Both are set to 15mA now. I have added some pictures :

    http://www.dcx2496.fr/sansui310.php

    Thanks again.
     

     

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  7. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    47,350
    Location:
    Hertfordshire, UK
    Just looked at the pics - What a superb cleaning job! :tresbon:
     
  8. terii

    terii Active Member

    Messages:
    302
    Location:
    Paris (France)
    hi:scratch2:
    look at the pics,you have an expert at cleaning for the vintage electronics
    congratulation:thmbsp:
     
  9. spaceman

    spaceman Registered Lunatic

    Messages:
    14,841
    Location:
    Seattle
    Nice work! :thmbsp: I don't recall ever seeing that line before, maybe not sold in the U.S.? Although it's a different animal altogether from my 7000, I see some similarities, like the vent cutouts in the wood case, & similar knobs. The early 70's gear is my favorite so far, until I find some tube gear anyways. :smoke:
     
  10. brucered

    brucered Well-Known Member

    Messages:
    701
    Location:
    Winnipeg
    there is a nice looking 210 i was thinking of picking up at a local shop, but they want $30CA for it right now, it looks to be in very nice shape.

    think it's worth it, or should i wait for the price to drop?
     
  11. nosirrah

    nosirrah Moderator Staff Member Moderator Subscriber

    Messages:
    7,453
    Location:
    30 min north of seattle
    310

    I had a 210, that's where this whole mess started, nice little receivers.
    Welcome to AK! Our happy little group of Sansui advocates are always looking for new folks, I will look at Manual Manor {storage unit} and see if I can help with the service manual for it.
    Casey
     
    KentTeffeteller likes this.

     

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  12. brucered

    brucered Well-Known Member

    Messages:
    701
    Location:
    Winnipeg
    alas, it was SOLD when i went back the next day. i have to learn to just BUY IT and worry about what i'm gonna do with it later.

    oh well, my search continues for a vintage receiver to play around with.
     
  13. John Peplau

    John Peplau New Member

    Messages:
    9
    I have a 210 with a non-working signal strength meter. It does deflect when I tested it so it’s good. Doesn’t work for am or fm. I can’t find the service manual. Hi Fi Engine only has the small manual with what appears to be a two page schematic copy cut in half. Anyone ever had this problem ?
     
  14. kevzep

    kevzep Its all about the Music

    Haha, snap, I have one on the bench at the moment with exactly this problem, among others. I'll let you know what I find.
    I have found some other issues in the tuner but haven't got as far as working on the meter problem yet.
     
  15. John Peplau

    John Peplau New Member

    Messages:
    9
    I just cleaned the function control switch so it’s not that. Funny thing about the am and fm pots for the meter. Neither swipers are connected. It’s just like having a resistor in circuit !
     
  16. John Peplau

    John Peplau New Member

    Messages:
    9
    Sorry, wrong schematic ! Too many circuit copy’s on my bench.
     

     

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  17. John Peplau

    John Peplau New Member

    Messages:
    9
    I have 0.0 volts at VR 201 & 202. 11.8 volts at leg of T203 for TR204 and 11.8 volts at junction of R228 & R231. TR204 Baseahas 11.6 volts. Everywhere else is 1.6 to 0.0 volts in that area. Checked ESR of some electrolytics in circuit but they were OK. I'm drowning here !
     
  18. kevzep

    kevzep Its all about the Music

    The problem with the meter not working on the 310 I fixed today, was two weak transistors in the IF chain.
    When I went to align it, I wasn't getting much signal out of the discriminator, so I threw an antenna on it, and it could only pick up one station, and it was a bit distorted. Basically the tuner was almost completely deaf.
    So I put new transistors through the entire IF chain and Local Oscillator, turned it back on and there it was, pulling in all sorts of stations, and it was miles out of alignment, and the meter working.
    So I then went ahead and aligned the IF, and discriminator.
    Next problem, no FM stereo. So the 19khz pilot was making it to the trap, but again around the 38khz doubler there were leaky old transistors again, so I replaced all the transistors in the Multiplex, and adjusted the 19khz trap, and set the multiplex threshold and it was all working perfectly.

    If you are going to replace transistors in a tuner, you will need to align it, everything was a fair ways off after I fitted new transistors.
    But now the owner of this will be ecstatic with the repair, as initially I told him it may not be an economical repair...

    So this tells us that with these ageing units with very old and early transistors, they are going to give trouble and should be replaced.
    It would save a lot of time, just to sweep right through and replace all transistors...
     
    Last edited: Mar 21, 2018
    Hyperion and skippy124 like this.
  19. John Peplau

    John Peplau New Member

    Messages:
    9
    Well, as of today I realized that the unit is a Sansui 210. Anyway, all the transistors were replaced along with, diodes and electrolytics, on the tuner board . Voltages week in front of the meter. Next will be to change all the caps on the power board. If nothing, then get the signal generator and scope out, to do this right.
     

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