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Thursday, 24 August 2017

Oddball prototype Linn LP12 power supply. The Linn Wakonda.

I'm just posting this because I'll probably never see another. Apparently there are only a slack handful in existence ...

It's a prototype Linn LP12 power supply. Apparently called a Wakonda, it's a bit like a bastard son of a lingo and an axis (of evil), with a hole in it!


It's a pukka job. Obviously some sort of prototype...


It's obviously had some use as the board has discoloured from heat underneath the droppers, and, as usual, a re-cap restored operation ..... except 45 RPM....

... which was traced to two missing pull down resistors, not catered for on the board, and never fitted... perhaps the previous owner didn't have any 45's ??!

One interesting feature is the output transistors are bonded to the heatsink with some sort of cement. The digital phase generator is almost identical to a lingo, and allows LP12 users to switch between speeds without all that tedious mucking about with the belt.

Here's some photo's of it's final resting place






9 comments:

  1. Fascinating, thank you for sharing. I always associate droppers either as cost cutting or bad design. Linn???? So close to the electrolytics as well... Hmm. Still damned interesting though!

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  2. Hi Andy,
    I have just purchased a Mitsubishi MC8000 and hoping to get it all working again - I have read your blog entry from 2016 when you fixed a unit (didn't sound too much fun).

    A quick question before I get working on the unit - i see that there are a few places to buy replacement belts, but I can't find too much on replacing the bulbs that control the record player arm - can you recommend a website that will help me buy replacement bulbs?

    Many thanks - Gary

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    Replies
    1. Hi Gary. Whereabouts on the planet are you?

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    2. Hi Andy - I am in Salisbury, UK

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    3. Measure the belt, and order the nearest size from cpc.co.uk
      The bulbs you can replace with a common yellow LED, with a 470 ohm resistor in series.

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    4. I *think* (can't be 100% sure) that this is the tt belt. http://www.ebay.co.uk/itm/TURNTABLE-DRIVE-BELT-FRX21-FRX24-5-diameter-170mm-200mm-5mm-Wide-/221579213723?hash=item3397267b9b

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  3. Hi Andy,

    Thank you! I must admit I am not really an expert on electronics, so I will start taking it to pieces over the weekend and see if I can establish what is blown or broken.

    I checked eBay via your link and found a Germany company that supplies all belts required, so I have ordered those (just so that I can renew them all).

    I know that the light that shines down over the centre of the record is not working - is that one just for show, or does it fulfill a function?

    Many thanks - it's just good to have someone to check with as I go.

    Gary

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  4. Replies
    1. Gary, If you need anymore help, just post up on the relevant post. Helps keep things tidy ;)

      http://andydoz.blogspot.co.uk/2016/06/mitsubish-mc8000-audio-system-repairs.html

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