Just got a Au x1 and of coarse need info

Discussion in 'Exclusively Sansui' started by Bigdrive, Aug 5, 2017.

  1. Bigdrive

    Bigdrive New Member

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    Here is the new foot print.....better but if you look closely you can tell the contact in the middle is not great image.jpg
    Best it's going to get unless someone has an idea?
     
  2. slimecity

    slimecity Super Member

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    Unless someone thinks differently, I cant see this being a big issue as the purpose of the thermal paste is to transfer heat, and this would include from areas of the trannie not quite contacting the heatsink in places? It appears that the trannies are mostly contacting the heatsink.....?
     
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  3. Bigdrive

    Bigdrive New Member

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    IMG_4493.JPG Here is the first side as removed after thermal grease applied and would have been put in service. As you can see, no contact between legs
     
  4. Bigdrive

    Bigdrive New Member

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    Post #63

    Trannie=transistors darn spell check
     
  5. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Last edited: Sep 6, 2017
  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    +1 - I wouldn't worry too much about 2½ thou, it isn't ideal but the heatsink compound will take care of that.
     
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  7. Bigdrive

    Bigdrive New Member

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    IMG_4495.JPG Does anybody have a good source for the 3.9 ohm 20watt power resistor? I have tried digi, mouser,Newark, google and some smaller shops. The closest is 4 ohm 20watts @ 5% which is within tolerance of 3.9 @ 10%. Unfortunately it's from china and is going to be 3-4 weeks.
    Any suggestions?
     
  8. Hyperion

    Hyperion Roobarb & Custard Subscriber

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  9. Bigdrive

    Bigdrive New Member

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    Do you think the lower wattage will matter if I just use it for testing and easy listening???
     
  10. Willy6

    Willy6 AK Subscriber Subscriber

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    I put a 25W 3.9ohm 5% resistor in mine and it works fine..Available at mouser or digikey..
     
  11. Bigdrive

    Bigdrive New Member

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    IMG_4497.JPG Waiting for shipment from mouser, I decided to catch up with trimmer pots on mc 2917/2918. Note these boards will not be installed in unit until I get a MC cartridge, which could be years.

    I remove old ones and take measurements to rough in a adjustment on the new pot. All pots have been as per SM, but these two. They read 205 and 185 ohms across the outer pins and are marked 220 as per picture. They are suppose to be 100 ohm by SM. I know many have said replace what you take off, not what's in the SM.

    I think Harolda found one wrong one one his amp that he thought had been installed wrong from Sansui. These two also look original solder joints.

    So what does everybody else have in those positions?
     
  12. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Well, you have two boards to look at, and it would be very unlikely that Sansui would made a mistake with both, and your amplifier has worked with the values in it now - I say put in 200 ohm replacements as per original - I can't remember what I put in mine.
     
  13. Bigdrive

    Bigdrive New Member

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    True.

    I have learned from you that you don't change from what's there!

    The voltages were set both before I started and after I recapped but I never heard the board as I don't have a MC cartridge.
    I don't think Sansui made a mistake in installing them, just that in the SM there is a difference between it and my model.

    Someone else should have come across this other than just me.

    Seems there should be a resistor change also. I will check skematic for other differences.

    Also can anyone recommend binding post. I have some from digikey but don't like them. Yes I like the gold ones that can short out! I don't have access to equipment other than a drill:)
     
  14. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I agree the binding posts don't age well, I'd like to think they felt more robust when they were new :)

    This is a great amplifier, don't cheap out on binding posts - spend a little more to make it much less likely that a short could take out as many as six :yikes: :bye: of those precious OP transistors - don't you think?
     
  15. ghamilton

    ghamilton Super Member

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    This is what I did for the binding post.....http://audiokarma.org/forums/index.php?threads/919-binding-posts-replacement.243497/
     

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