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CASIO Keyboard Power

Discussion in 'Troubleshooting and Repair' started by AndrewD, Apr 10, 2018.

  1. AndrewD

    AndrewD

    3
    1
    Apr 10, 2018
    Good afternoon,
    Glad for advice to get my 2nd hand keyboard working!
    Model CTK501, bought from Ebay (perhaps bad idea!): indicator light not on.
    Packaging was not great but no obvious damage or other symptoms.
    Seller positive it works; sent photo with keyboard light on.

    9V power adapter works - light on, tested by PC shop today.
    That has 2 pin connector between lead from adapter to dc probe to device.
    Believe it reverses dc power by inserting pins 180 degrees round. But unclear which way gives positive to central probe?
    (Probe is very narrow and not tight in keyboard connection).

    Possible when I first tried it was wrong way! Would that have blown input stage in keyboard?
    (or should it is be protected by a diode?)
    Have since tried in both ways.

    I can buy new dc adapter (about £9-15) but may not get me far: is this only way to diagnose?
    While I have electrical knowledge and multi-meter, if I open up keyboard I have no other diagnosis kit.

    Thanks for any help, in advance,
    AndrewD
    (no photos useful yet)
     
  2. hevans1944

    hevans1944 Hop - AC8NS

    4,214
    1,994
    Jun 21, 2012
    Well, lucky you. It does appear, from reading the schematics in the service manual, that there are protection diodes to prevent damage from applying an external power supply with reversed polarity.

    Why have you not installed six D-size cells to test functionality before attempting to "brick" your keyboard with a 9 V DC power adapter that has the wrong plug connected to it? Try downloading and reading the service manual for this keyboard. If it doesn't make any sense to you, try making contact with a Casio authorized service facility.
     
  3. AndrewD

    AndrewD

    3
    1
    Apr 10, 2018
    Thank you very much hevans1944,
    Dumb of me to forget trying batteries to test it!
    Thanks also for manual link, only one I had found was wrong model.

    Will try in few days time and advise if anything found of interest to others.
    Andrew D (1947!)
     
    hevans1944 likes this.
  4. hevans1944

    hevans1944 Hop - AC8NS

    4,214
    1,994
    Jun 21, 2012
    It is extremely important that you find the right-sized barrel-plug for the external power supply. "Close enough" is not good enough. It must be exactly the right size, and fit snugly in the receptacle without side-to-side "play" and without falling out. Loosely fitting plugs are an invitation to an intermittent electrical connection, leading to possible early failure of the electronics, not to mention noisy operation of the keyboard. Get this part right or be satisfied with using rechargeable D-cells.
     
  5. AndrewD

    AndrewD

    3
    1
    Apr 10, 2018
    Quite agree re tight fit of power plug. Experienced flaky electronics in warships during my RN service many years ago!
    Glad to report new batteries have worked! I owe you at least a bourbon bottle or similar.
    Will start learning with batteries then advance to a new power feed.
    Many thanks
    Andrew D
     
  6. hevans1944

    hevans1944 Hop - AC8NS

    4,214
    1,994
    Jun 21, 2012
    So glad to hear your earlier adventure did not "brick" your keyboard! No bourbon necessary, just glad to be of some help here.

    A few years ago, in the previous century, I fancied I might want to do something "electronical" with music. So I purchased a Roland synthesizer, a MIDI piano keyboard, a stereo receiver/amplifier, and boxed up a pair of automobile speakers (designed to mount in the car doors) and attempted to "make music" with that rig via my personal computer. And just for good measure, I also purchased a slightly used Conn electronic organ. Long story short: I was able to produce loud sounds but apparently had zero talent for producing anything resembling music.

    I became disillusioned with the type of "music" the synth and its MIDI interface could produce: it all sounded so "mechanical" and un-natural to my ears compared to the sound that real musicians, even poorly trained ones, could bring forth from their instruments. Our teenager children and their friends formed a "garage band" that sounded better than anything I could "play" with my Roland and MIDI keyboard... and that's not saying much as I thought their music was mostly just loud, while screaming hoarsely rather than singing.

    Eventually the teenagers grew up and left the house to pursue their own interests. I decided to give up on the electronic music about that time too. Computers, hobby electronics, and amateur radio occupy a lot of my time today.
     
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