Replacement filter caps for AU-919

Discussion in 'Exclusively Sansui' started by lbcgav, Jul 24, 2018.

  1. lbcgav

    lbcgav AK Subscriber Subscriber

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    I've narrowed down my search to the following two Nichicon caps:

    LGU1J103MELC.......$5.54...10,000uF...63V...105 deg...3,000 hrs...4.69A @ 120Hz, 5.3935A @ 50kHz ripple current...Total cost: $44.32

    LGY1J103MELC50...$7.89...10,000uF...63V...105 deg...5,000 hrs...3.8A @ 120Hz, 4.37A @ 50kHz ripple current...Total cost: $63.12

    Dimensions are the same, 35 X 52 mm. If you had to choose between the two, which would you choose?
     

     

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  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I would choose the first one mostly because of the ripple current rating, and they are cheaper. Unless you listen at concert hall levels you'll be unlikely to need anything beefier than that. They will get an easy life as most audio amplifier main PSU capacitors do*.(*non-class A). So there is a good chance they will last a lot longer than the spec' 3000 hours, especially as you will have 4 pairs of 2 in parallel.

    But don't take my word for it, :) there may be reasoned arguments for either choice.
     
    Last edited: Jul 24, 2018
  3. lbcgav

    lbcgav AK Subscriber Subscriber

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    I was leaning towards that one, but I thought I'd ask if I was missing something. Will 63V be high enough?
     
  4. ghamilton

    ghamilton Super Member

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    If you have done the rest of the amp FIRST, then maybe. Leestereo's said that sometimes those big ones don't need replaceing.
     
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  5. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Quite so, they should be the last thing you do when reconditioning your AU-919, I've done 3 in all, 2 of them didn't need it, and I only did my own 'because I can' - and I wanted to see if there was any difference, and just how good it could sound with all the other stuff done.
    63V is high enough - but only just, I can't remember if I used 80V or 63V rated capacitors in mine, (my AU-919 PSU Cap U/G thread should show it) and maybe capacitor size (diameter in particular) comes into play here. (NB: I'll check tomorrow and update here what voltage rating I used - I think it was 80V having thought about it some more)
     
    Last edited: Jul 24, 2018
  6. lbcgav

    lbcgav AK Subscriber Subscriber

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    Thanks John. I know Kale used 100V, but I saw that ScottRT used 63V, and he did some for EchoWars, so I would think 63V would suffice if EchoWars didn't complain about the 63V rating.

    So, did the capacitor change make a difference on the one you did it on?


    Correction, Kale used 80V.
     
    Last edited: Jul 24, 2018

     

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  7. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Not as far as I remember, the change if any was too subtle to be sure of. If there was a change, after already having reconditioned the rest, it had the best chance of showing itself, but nothing particular was noted.

    Here is the link to my upgrade thread
    http://audiokarma.org/forums/index.php?threads/another-au-919-oval-capacitor-upgrade.561441/

    And I did use 80V replacements. :)

    Seeing my thread again reminded me of the reason for my replacement/upgrade was that I was concerned to see the different ripple voltage on either channel. And you'll note that the before and after figures for one channel are pretty much identical. The other AU-919 examples I have worked on did not show any difference, so no replacement was recommended.
     
    Last edited: Jul 25, 2018
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  8. Kale

    Kale Super Member

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    I just made one update in my thread about restoration of those oval capacitors, very important thing is the way how you connected capacitors inside of oval housing....
     
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  9. lbcgav

    lbcgav AK Subscriber Subscriber

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    Thanks everyone for all the updated information. I got a chance to take out the large oval capacitors and did some measurements. According to my little multi-component tester, the caps measure approximately 15 mF (15,000 uF) and extremely low ESR. So, I won't be replacing these.

    Some other good news, the original output transistors all tested good as well.
     
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  10. ghamilton

    ghamilton Super Member

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  11. lbcgav

    lbcgav AK Subscriber Subscriber

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    I've been going over Leestereo's restoration thread and it appears that he did not replace the trimmers on the flat amp and the head amp, just the Bias and DC offset trimmers. Should these other trimmers be replaced as well?

    One other thing. It appears the thermal grease used between the two sandwiched heat sinks is different than the white silicone based grease I'm used to. It's clear and closer to a vaseline consistency. Can I just clean this up and use the regular white stuff?
     
    Last edited: Jul 26, 2018

     

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  12. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    In my opinion yes, I strongly recommend changing trimmers - they can be the source of much grief.
    The clear vaseline stuff will be Silicone Grease, the (paper) white stuff is better if properly (thinly) applied, so another yes. :)
     
    Last edited: Jul 26, 2018
  13. lbcgav

    lbcgav AK Subscriber Subscriber

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    I think I take your helpfulness for granted. Thanks for your quick reply, as usual.
     
  14. lbcgav

    lbcgav AK Subscriber Subscriber

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    I've had a pit in my stomach since last night, when I went down to a workshop at my work where I've been storing my AU-919. I started to take the partially dis-assembled amp out of the bins I was storing them in when realized that I was missing the cup I placed all the screws that hold the covers, chassis, and boards together. These are those little black and silver screws. Also, the output transistor screws were in there as well as the screws that hold the filter capacitors in place. Even worse, I placed all the knobs, wrapped up in a rag inside of the same cup. The only knob I now have is the volume knob and one of the flip switch covers. Thankfully, still I have the precious output transistors and all the other parts besides the screws and missing knobs. I think I can still salvage this with some overpriced eBay purchases.

    A couple questions: 1) The part numbers for the flip switch covers are slightly different on the AU-717 vs. the AU-919. Does anyone know if the AU-717 covers will work on the AU-919?; 2)Does anyone have the measurements for the a) output transistor screws; and b) the filter cap screws? In addition to these crucial questions, does anyone have a source for those evasive chassis screws Sansui uses by the bucket-load? I've found near-facsimiles, but never an exact match.
     
  15. JoseHH

    JoseHH Member

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    How certain are you that the cup were you had those parts is ireversibly lost?. Perhaps it is missplaced somewhere in the shop. I hope you find it.
    The screws for the output transistors appear to be pan head, philips type, nickel plated brass screws, metric thread 3mm and 16 mm long. Stainless steel may be used as well.
    With regards to the switch covers, the ones in my AU-D907 appear to be identical to those in m AU-517 and my AU-317II. I am not sure if Sansui made different versions of these parts but it seems unlikely to me. The aluminium knobs could be machined from 60601 alloy and then send to black anodize. They have a very fine sand blast finish and jet-black hard anodizing. It is not mate blackanodizing. They have a line engraved which is painted. I can measure my knobs and send you the dimensions if you need to make new ones. Hopefully you recover your original parts.
    Good luck!!
     
  16. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I think you'd be favourite person around here if you found that out, many have tried and failed, yours truly included. :)
     

     

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  17. lbcgav

    lbcgav AK Subscriber Subscriber

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    I've gone through every inch of this place...even the dumpsters. Unfortunately the trash came yesterday afternoon and most likely took the cup with it. Thank you for the measurements of the transistor screws! That's very helpful. I think the size of most of the screws for the chassis is an M2.9 X 8mm screw. The longer ones are probably M2.9 X 10. The knobs are the same as the AU-717, so I can buy some off of eBay. I think I have all the info I need except for the screw size for the filter capacitors.

    Indeed! By the way, you spelled favorite wrong;).
     
  18. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Not wrong from where I come from, actually you've spelt it wrong. :D
     
  19. lbcgav

    lbcgav AK Subscriber Subscriber

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    Geez, you don't even know how to spell "spelled" correctly! Don't you know how to speak 'Murican?

    More on topic, I bit the bullet and bought off of eBay 3 tone control/speaker/tape selector knobs (p/n 5318840), the Selector knob (p/n 5318830), and 4 of the lever switch covers (p/n 5326611). I'm hoping there is no significant difference between the lever switch covers for the AU-717 (5326611) and the AU-919 (5326612). I guess I'll find out in a few days if they work. So, after these purchases, I'll still need a balance knob (p/n 5318850) and one more tone control knob (5318840). That'll be it for the knobs. The eBay guy I bought most of the knobs from said he'd see what screws he has left over from the teardown of the AU-717 and he'll throw them in the package with the knobs.
     
  20. kevzep

    kevzep Its all about the Music Subscriber

    Not wrong where I come from too!!
     

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