Hunting for a psu.

  1. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
    11,296
    Location:
    Bedfordshire England
    Won an old analog mixing desk for a pittance.

    To big for me right now so cleaning up the internals and making sure everything works as it should is a winter project

    The downside
    No power supply.

    Needs a 6 rail psu.
    See schematics below.
    Seck 1882


    Anyone have any ideas that might do the job.

    Company makes replacements but none available and haven't heard back from them yet .



    seckpsu.gif Screenshot_20200628-221652.png Screenshot_20200628-221646.png
     
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  2. Kayos

    Kayos Member

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    The only oddball in that is +/- 25v, +/- 15 and 48v is pretty standard in a lot of audio gear

    With modern tech I doubt making a replacement would be hard, making it fit the space would be another thing

    I once built an amp that had +/- 50v rails, close enough to the supply a 110 transformer kicks out, never had any issues with supply sag unsurprisingly
     
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  3. eLuSiVeMiTe

    eLuSiVeMiTe Member

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    Space is a non issue as it's an external supply thankfully.
     
  4. eLuSiVeMiTe

    eLuSiVeMiTe Member

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  5. Hopefuldave Intergalactic pot-mender

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    Location:
    The Shed of Danger, surrey, England
    Nice desk!

    It's a pretty simple linear PSU, shouldn't be hard to DIY - the 48v is only there for phantom power, so if you don't use condenser microphones it's not essential - handy too have if you do, though!

    One suggestion - have a long lead on it, I rebuilt/modified a rather bigger Soundcraft modular desk for a fiend-of-a-friend, he was complaining that after it was done he could hear a hum through the headphones and got huffy about paying for the work, I had to go round and get him to demo the hum - "is it still there in the 'phones?"
    "Yeah, a background hum coming through"
    "Interesting, I've just unplugged 'em"
    "Eh????"
    it was the transformer in the PSU humming, had to make a long cable to move it out of the room - cost him a bit extra ;)

    Dave H. (the other one)
     
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  6. WorkshopChris

    WorkshopChris Forum Supporter

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    Glad you said that I was wondering the same. The only thing I was wondering was if it was doing anything else maybe an internal relay seams a little unusual to have a switch on an external PSU.
    Is there a master phantom power switch on the front panel anywhere?
     
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  7. eLuSiVeMiTe

    eLuSiVeMiTe Member

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    Believe so yes. Picking it up later. Don't/won't need phantom. Have 18 phantom inputs already I don't use

    I did wonder about diy but simple for one doesn't mean simple for me. Anyone fancy an idiots guide. Soldering is no issue.
     
  8. eLuSiVeMiTe

    eLuSiVeMiTe Member

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    Location:
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    Afaik soundcraft bought seck from the little reading I did

    Suppose I better start doing some homework. Certainly not my area
     
  9. eLuSiVeMiTe

    eLuSiVeMiTe Member

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    Oh. Heard back from the company. There not new psu so only become available when they get a desk to break for parts

    On the flip side they do have plenty of spares if needed
     
  10. MCKDAVID Member

    if you get stuck, I have a good electronics guy here, he'll make up / adapt / repair anything you like, might not be cheap, but will definitely make it work. He's bailed me out a few times with repairs of obsolete boards.
     
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  11. WorkshopChris

    WorkshopChris Forum Supporter

    Messages:
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    Location:
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    Shouldn't be too complicated to organise something.
    looks like its just the 15v rails that are regulated anyway. Lots of good kits to possibly use as building blocks are available.

    https://quasarelectronics.co.uk/Item/3114-25v-2a-dual-polarity-unregulated-power-supply
    https://quasarelectronics.co.uk/Category/kits-modules-positive-negative-power-supplies
    https://quasarelectronics.co.uk/Category/kits-modules-power-suppy
     
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  12. eLuSiVeMiTe

    eLuSiVeMiTe Member

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    Will have a look through those later cheers.
    Got to run out to pick up the mixer soon.

    Just wasted half hour testing the adat that just arrived

    Bloody couriers had the box open.
    Removed the leads and rack ears took the bubble wrap off the unit and shoved the unit back in the box.

    Scrounged a lightpipe from the tv/stereo connection and thankfully the unit seems to be working as it should

    Will test all the in/outs tomorrow.

    Il poke through the PSU schematics when time permits and see if I can list the components.
     
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  13. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
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    Mug for scale
    A lot lower profile than I thought. Weighs a chunk though.

    Looks pretty straight. 1 bent fader easily sorted

    Need to browse the manual and see what the hole is.

    All the trs inputs look to be missing locking rings too but should be easy to track down something suitable.

    Best buy some more iso.
    Stinks of tobacco. :/
    If it costs me a ton to buy/make a psu it's still a bargain
     
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    Wallace likes this.
  14. awemawson Forum Supporter

    I'd be tempted to buy individual psu's that together make up your combination of voltages. Nothing there particularly exotic that eBay cannot provide, then house them in a suitable box.
     
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  15. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
    11,296
    Location:
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    That thought occoured to me first

    If I buy one of the supply's for the smaller models they have all but the 25v rails iirc
     
  16. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
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    Location:
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    Bit more info on the supply.
    Found a service manual which will come in very handy
     
    • Screenshot_20200701-194833.png
  17. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
    11,296
    Location:
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    Hopefully I'm lucky with this unit. Was sold as a working desk but the chap who drove to Wales to pick it up forgot the Psu.
    Seller refused to post and out it on eBay.
     
  18. Seadog

    Seadog Forum Supporter

    Messages:
    6,011
    Location:
    NE London - UK

    It's quite possible that they were never fitted. Are there any witness marks on the panel? If you decide you need them I may have some nuts to suit. They're 3/8" x 32tpi ME thread which are for BNC connectors or pots.
     
  19. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
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    Location:
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    Will have a check and if they will do it that would be appreciated Graham

    Judging by the flex in the board when I press the buttons near the top they were relied on to secure the board
    Possible they were plastic
    Il get a close up
     
  20. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
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    Location:
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    IMG_20200701_213255.jpg
    Really does need a good clean
     
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