Yamaha Electone FX-20 re-cap

Discussion in 'Yamaha' started by Electone, Jan 5, 2017.

  1. Electone

    Electone Well-Known Member

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    I know this is not your typical thread as it is about a musical instrument, but it's a Yamaha and it has audio amplifiers and power supplies just like an audio receiver or amp. I thought it may be an interesting read...

    The Yamaha Electone FX-20 was manufactured from 1983-1987 and was the flagship home model based on the stage model FX-1. It cost a whopping $23,000 which translates to $55,000 today :yikes:. I paid $300 for mine a few years back :banana:. This was Yamaha's first foray into digital synthesis technology in keyboards and has both FM generated voices and digital sampling. It also has a massive sound system with 210 watts of power that can shake the foundation of your house. Many of you will recognize the name Yamaha GX-1 as played by Keith Emerson, Stevie Wonder, Benny Anderssen and John Paul Jones. Same family of instruments, except a decade newer.

    My plan is to re-cap the massive power supplies and amp board in this beast. There are thousands of electrolytic capacitors in this instrument on hundreds of circuit boards. Changing out each one would be a monumental task.

    The FX-20:
    [​IMG]

    The power amplifier power supply unit has 4 Nichicon CE caps. 2 x 10000uf 55v, 2 x 10000uf 65v. Also, it has several smaller caps on the underside of the unit. They have been replaced with Cornell Dubilier SLPX 10000uf 63v & 380LX 10000uf 80v. All smaller caps will be replaced with Nichicon PW. The original Nichicon CE caps were four-lug with the wires wire-wrapped around the lugs. The CDE caps are two-lug and what I did was to install bullet connectors.

    PA power supply:
    [​IMG]
    Bottom:
    [​IMG]
    Bullet connectors (male & female) installed on new caps:
    [​IMG]
    Old Nichicon CE and new CDE with female bullet connectors crimped and soldered in place:
    [​IMG]
    Completed PA power supply (notice how much smaller the CDE caps are):
    [​IMG]

    Next up will be the instrument's main power supply. It has two massive transformers and one oddball Nichicon CE cap rated at 28000uf, 16v. I've checked for a replacement and cost is quite prohibitive. So, I tested it and it seems fine. I'm going to leave it for now. The smaller caps on the huge heat sink will be Nichicon PW. Top side of the main power supply:
    [​IMG]
    Bottom side has 2 x 6800uf 35v, 3 x 10000uf 16v & 3 x 6800uf 25v. These will be replaced with CDE SLPX caps:
    [​IMG]
    Third power supply unit supplies power to the panel lights and some accessories. Nichicon PW for this as well:
    [​IMG]
    Main amplifier. Top half is the 90 watt center channel with a STK089. Lower half is the 60 watt x 2 left & right channels with STK085.
    [​IMG]
    Since it's in the general area, I'll recap the expression pedal as well:
    [​IMG]
    This is the now empty lower half of the instrument. The PA power supply sits on the far left, the expression pedal just to the right of the big woofer. Behind it sits the PA and to the right is the main power supply. There is miles of cabling in this thing.
    [​IMG]

    Well, that's where I am right now. I'll post an update when I'm done.
     
    Last edited: Jan 5, 2017
  2. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Which Electone models had V-fets?

    nashou
     
  3. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    What a beast, how is the power supply/power amp rebuild going?
     
  4. Oilmaster

    Oilmaster Ozzy Subscriber

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    So cool to see that beast here !!!!
    You'll have my respect for that task !!!! :confused:

    PS: for some reason I only see the first photo :(
     
  5. Electone

    Electone Well-Known Member

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    Bloody Photobucket's new policy has screwed up a lot of forums all over the net. Tons of hosted photos no longer visible because they want cash for hosting now. I'll have to see if I can dig them up again.
     
  6. Electone

    Electone Well-Known Member

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    669
    Location:
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    Rebuild went perfectly. I tested the caps that came out and they were all fine. But, having fresh caps in the power supplies and amp boards is good maintenance.
     
  7. Oilmaster

    Oilmaster Ozzy Subscriber

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    Oh yeah, that sucks;
    Photobucket is becoming Photobuck :deal:

    Recently logged into my account, and my PC had a near crash due to the tons of pop-up ads.
    I am going to delete all my photos and I'll never come back there; sorry for all the photos that may disappear from AK, but we have to draw a line against golddiggers like that.

    Anyway, just a few photos would be nice :)
     
  8. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    Yes definately a very good idea, does she all work?
     
  9. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately... Subscriber

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    Amsterdam Area, The Netherlands
    Wow, this is awesome :bigok:

    Yeah, Photobucket. Been there.. Had to replace all pictures in my 15 pages counting B-2 resto :crazy:
     
  10. Nashou66

    Nashou66 AK Subscriber Subscriber

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    Anyone?
     
  11. Electone

    Electone Well-Known Member

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    Yes, works perfectly. Even all the motorized sliders work - and that is rare.
     
  12. Electone

    Electone Well-Known Member

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    669
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    Sorry, no idea.
     
  13. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    That's great, l have zero knowledge of these but it sounds like there is a huge amount of internal components so for it all to be working at it's age must be a huge plus, Are they generally fairly reliable?

    You have my interest with your project as l used to play piano and keyboard, fairly rusty these days though :(.
     
  14. turnitdown

    turnitdown Not well known Subscriber

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    May I say..."just wow!"
     
  15. zaibatsu

    zaibatsu Active Member

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    441
    Add me to the list of people who'd love to see the pics of the internals, that's so cool!

    Bit of a side question - do you know what components are used to generate / control touch sensitivity in these instruments?
    I've got an old Technics KN-2000 synth / kb with one key's touch sense failed, would like to fix it one day if it's not controlled by unobtainium.
     
  16. Gazdatronik

    Gazdatronik Super Member

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    Its likely a two stage membrane. Looks like a racetrack. Clean the circuit board and black carbon contacts. Should fix it right up.
     
  17. Electone

    Electone Well-Known Member

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    669
    Location:
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    On some instruments, they use a rubber contact pad with two carbon strips. When the first strip touches, you get one level of volume, keep pressing harder and the second strip touches and volume increases. But the Electone keyboards have an incremental increase in volume plus inital/after touch, so I'm thinking it is more complex than that.
     
  18. Electone

    Electone Well-Known Member

    Messages:
    669
    Location:
    London, Ontario, Canada
    Well I managed to find some before photos, unfortunately, the "after" photos are history. Edit: well that's weird - adding photos to Tinypic and somehow, the photos showed up in the original post...

    Amplifier power supply:
    [​IMG]
    Amplifier power supply bottom:
    [​IMG]
    Main power supply:
    [​IMG]
    Main power supply bottom:
    [​IMG]
    Console lamps power supply:
    [​IMG]
    Amplifier:
    [​IMG]
    Expression pedal:
    [​IMG]
    Empty lower area and speaker system:
    [​IMG]
     
    Last edited: Sep 18, 2017
  19. Oilmaster

    Oilmaster Ozzy Subscriber

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    Thanks for posting the photos.
    Soooo cool to see this stuff.
    I think it does belong here very much; it's Yamaha audio gear after all :)
     
    Oldsansui441 likes this.
  20. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    1,191
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    +1 on this, well said.
     

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