Baby Grand Piano

Discussion in 'General Electronics Chat' started by pianomike1957, Jan 1, 2013.

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  1. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    Hello. And thanks for the forum.

    I have a Technics SX-PR1000 baby grand piano/multitrack synthesizer (over $10K new) that has a main-board problem and I'm not quite ready to say uncle and make the whole piano a boat anchor just yet.

    The problem is I get a blue screen and several of the buttons light up sometimes, sometimes not, no sound at all, etc. It changes on power up. Sometimes the main menu will pop up and the buttons (for the synth.) seeem to work, but no sound out of the piano keys. And again, on power-up, sometimes I get just a blue screen and nothing else.

    I have researched this extensively. It seems to be a consistent problem with these. They are no longer made and replacement boards do not exist. There is only one guy in the world that claims he can rebuild them, he's in England, but he seems impossible to get a hold of. I'm suspect, but he does have a nice website so I'm sure he's on the up and up. He just doesn't have an email, and he never answers his phone.

    My electronic skills aren't tooo bad. I learned old school TV repair back in the day and have always tinkered with things. I suspect this is some kind of power supply problem. It does have a seperate power supply board, and I'm pretty sure this is OK, but what I'm thinking, and correct me if I'm wrong; the board in question, with all its chips and all the brains, takes the main power supply and then regulates and refines it further.

    I am suspect of these two transistors (they are only using two legs, the middle prong is not being used "?"), at least I hope its them. But here's the problem, even if it is them, I can't find replacements using that part number which is visible in the photo, and I'm not smart enough to check the properties and find an aftermarket replacement.

    I'll try and attach the photo and post this. Any thoughts comments or crazy ideas are all welcome. Thanks.
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    They middle lead may have been cut but the metal tab on the top is usually electrically connected to that leg as well. It looks like the designer has folded this chip back and soldered the tab to the board to allow the board to become the heat sink.

    The "transistor" on the right appears to have run hot because the board is slightly discolored around it. What numbers are on that part?

    The transistor on the right appears to be
    http://www.datasheetcatalog.org/datasheet/panasonic/SJD00031AED.pdf
     
    Last edited: Jan 1, 2013
  3. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    I think, re overheating, its just my photography skills (lighting). They are both the same part number however.
     
  4. bertus

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  5. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    Oh, on second look, you are right, there is discoloration.
     
  6. pianomike1957

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    Jan 1, 2013
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    OOps, my bad on the username. If you want to change it to just pianomike1957 its cool by me. Thanks.
     
  7. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    The username is changed.
    Next time you can login with the new name and existing password.

    Bertus
     
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  8. pianomike1957

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    Jan 1, 2013
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    Was I correct in my assumption that this part of this board is a "sub" power supply, ie being one that regulates the power for this board from the main power supply board?
     
  9. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    Gopher...... thanks for that PDF sheet, I'm gettin somewhere here.

    When I say I'm not smart enough to figure all that stuff out, I mean it. Thats Greek. But how do I order 2 of these? Any idea? I'll support the website here and order from whoever you say.
     
  10. tubeguy

    Well-Known Member

    Nov 3, 2012
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    You may very well have component issues, but don't overlook checking for simple bad/broken connections on the PCB's or interconnect wiring harnesses.

    Have you tried simply tapping different areas of the face of the piano whille on to see if symptoms change. ??
    (Not being experienced, you do not want to tap around under the hood when it's plugged in).
    You can gently re-seat connectors inside the piano with the unit un-plugged.
     
  11. takao21203

    Distinguished Member

    Apr 28, 2012
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    Have you tried the Panasonic Customer Communications Centre

    0844 844 3899 for the UK

    Panasonic UK
    Panasonic House, Willoughby Road
    Bracknell
    Berkshire
    RG12 8FP

    If the keyboard costed so much money, they have to care for these products, or point to a service center where they can do it.
     
  12. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    You better believe, I tapped and tapped. I tippy-tapped.lol:) I checked for all the obvious things that were prevalent in the old school days too, ....solder joints, cracks, etc

    I need to test those 2 transistors. I did not want to mess with them if I couldn't get new ones. I just don't want to make a bad problem worse. I take it i need to remove them from the board to test. Is that right?
     
  13. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    If the keyboard costed so much money, they have to care for these products, or point to a service center where they can do it.


    Its over 5 years old. They'll tell me to pack sand or pay $10000/hr to fix.
     
  14. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    Also, on the panasonic link (thanks for providing), it says "manual not available electronically".

    Even if it was, it, the "troubleshooting guide" as they call it, would probably just be the back part of the user's manual. The idiots guide.

    ---Step one.... make sure its plugged in.
    -----Step two.... turn it on




    I think I'll make that my quote
     
  15. takao21203

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    Apr 28, 2012
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    Worth giving them a call, or even sent them a formal letter requesting help.

    I would do the latter, and also mention purchase price, purchase date, and the dealer.
     
  16. tubeguy

    Well-Known Member

    Nov 3, 2012
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    Great answer :)
    Nice info for testing: (I would remove them)
    http://www.elexp.com/t_test.htm
     
  17. takao21203

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    Apr 28, 2012
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    The black battery on the photo might be dead.

    Also it's a good idea to measure voltages on the power supply capacitors, if any.

    If it sometimes powers up, and shows data on the screen, the power supply can't be dead. Likely configuration error, or corrupted FLASH.

    The ICs visible on the photo are so complicated, it is close to unlikely that anyone without information about the circuit would be able to test/repair it.

    But indeed, it is nothing more than a small computer- a controller + FLASH chips + custom chips, maybe RAM as well.

    Many consumer goods use obscure controllers which aren't available on the open market. Means they don't normally use PICs or Atmel chips.

    Even if you know all about the controller chip- without access to the firmware in the FLASH this won't help you much.
     
  18. absf

    Senior Member

    Dec 29, 2010
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    I'd agree with Takao, a circuit board this complicated wouldnt be easy if you dont have the schematics or service manual. Even with a service manual and you finally locate the problems, you still be facing problems getting the components.

    If your piano is only 5 years old, it would be considered quite new. The Yamaha Clavi promised that spares would be stocked for 10 years and we can even get components like chips and buttons that are 20 years old but not the complete PCBs..... Recently I just ordered the power supply + amplifier board for an 20 year electone EL90 (which also cost about $10K when new and that was 1990 money)

    You may start what ever you can do now and make sure all the supply voltages are there eg. +5V, +/- 12 or 15V for op-amps etc. It should be marked on the PCB and link with a plug from the PSU PCB to the digital and analog boards.

    Once all the voltages are OK, you'd need the schematics to continue to the next steps.

    I dont have much experience in repairing Technics organ or digital pianos. I only have very old service manuals like the SX-EX5L and SX-EX10L organs.

    I mostly repaired Kawai and Yamaha electones and clavinovas.

    good luck and cheers:)

    Allen
     
  19. takao21203

    Distinguished Member

    Apr 28, 2012
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    There might be one capacitor at the end of it's life, or one component from the power supply burned out. Or configuration error/FLASH corruption.

    All these things are easy to repair.

    If the FLASH is external, they need to reflash in circuit, or remove the chip, install a new one. FLASH memory has changed a lot over the past years. But these are not so uncommon.

    So this is where I would search first.

    Or something is broken terribly, and the firmware hangs up. I know that from PC mainboards, if the configuration is corrupted, nothing goes anymore. You need to insert a new battery, and reset the configuration. Or wait quite a long while.

    At least testing this black battery is worth trying.
     
  20. pianomike1957

    Thread Starter New Member

    Jan 1, 2013
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    'Worth giving them a call, or even sent them a formal letter requesting help.'

    Its a good point. I'm not the original owner though, but still, they might want to "save face" if I squeak loud enough. As I understand, Technics was taken over by Panasonic.

    Hmmmmm,... well, lets see what I can get done here. I've already learned a lot. I had no idea that one thing was a battery. There's some sharp cookies hanging out here. I perused some of the site, I'm like, these guys are scientists.
     
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