Casio CDP-230BRK keyboard repair (PCB)

Discussion in 'Introductions' started by Alaskandrummer, Oct 21, 2016.

  1. Alaskandrummer

    Alaskandrummer

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    Hi everyone, as stated in the header I have a Casio CDP-230BRK keyboard that I'm currently working on. The problem is that the keyboard will turn on, but will not stay on. I have to hold down the power button for the full power to remain on. While holding the power button down the keyboard is fully functional. Once I release the power button the display screen dims, but stays illuminated and I loose all functions of the keyboard. I have checked the 12VDC power adapter with my multimeter and it reads 12DVC. I have removed the entire 3 PCB boards and have found no visable damage at all that I can find. In my opinion the power button is a momentary contact, so there should be a failed component on the board which is not holding in the circuit. I removed the control buttons and found no visable damage either. They're just rubber strips basically. I found some videos online that showed and discussed cutting with a hold punch a piece of adhesive aluminum sheets to make better contact, but when I push the button to the board the keyboard responds just fine until I let go of the on button. So I don't think contact is a problem. Any ideas?
     
    Alaskandrummer, Oct 21, 2016
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  2. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    It obviously has some sort of latching circuit directly connected to the power supply board or rail and controlled or controlling the power on self test of the CPU in the keyboard.

    Troubleshooting this could be as simple as replacing a faulty power transistor or resistor or capacitor or as difficult as replacing the CPU on the motherboard.

    There's really no way to tell without going in there with the proper instrumentation.

    Either way, it's probably a solder job and since most modern boards are surface mount and not through hole design you're probably out of luck for a DIY repair. Working with surface mount requires specialized equipment and know how that most average hobbyists don't have.

    One final suggestion though.

    If it is failing the POST and shutting itself down and you've already checked for stuck buttons take a look at the keys and connectors. There may be a short in a connector or a stuck key switch somewhere that's causing it to fail the POST.

    Otherwise, send it in for authorized service. They don't do component level repair. They just swap out boards. :(

    Gary ;)
     
    happyrat1, Oct 21, 2016
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  3. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    One other possibility.

    The 12 Volt Casio Power supplies are REGULATED supplies.

    That means a nominal 12 volts RMS is not good enough. The ripple current has to be as smooth as a baby's bottom.

    Possibly the supply is delivering noisy power.

    Much cheaper to simply replace the supply than try to fix it in that case.

    If you can lay your hands on a scope then take a look at the output and check the ripple for spikes or anomalies.

    If you can't borrow a scope you can buy a cheap Chinese hand held scope these days that is good enough for the job on Amazon for around $75. A handy tool to have around for jobs like this.

    https://www.amazon.com/KKmoon-Pocket-Sized-Handheld-Oscilloscope-InterfaceFull/dp/B01C2LITEI

    When I bought mine I paid around $50 for it two years ago.

    Everything's gone up, including cheap Cheap Chinese Junk :D :p

    Gary ;)
     
    happyrat1, Oct 21, 2016
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  4. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    happyrat1, Oct 21, 2016
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  5. Alaskandrummer

    Alaskandrummer

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    Yeah thanks happyrat1, that's about what I figured. I am looking for a replacement PCB because like you said I figured that's what they would do if I sent it in. I got this for free and my friend said I can have it if I fix it (although he doesn't want it back anyway). I am having some trouble properly identifying the part numbers and proper terminology for replacing the PCB. This keyboard has 3 boards. I'm hoping to find them all together so I can just plug and play if I can find them. Does anyone know if there would be one number for all 3, or which number I have circled would be the individual part numbers? Also, although I did test the power adapter that was just a no load test. Is it possible the power adapter still may be the problem when I apply the load?
     

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    Alaskandrummer, Oct 21, 2016
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  6. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    While I have no idea what Casio's in house parts numbers would look like I just checked all my usual suppliers and nobody seems to stock any parts for that model.

    Don't give up hope yet though.

    Search Ebay daily for the next month and see if a busted one comes up selling for parts.

    Or just plug those board numbers into an Ebay search and see what comes up.

    Garry ;)
     
    happyrat1, Oct 21, 2016
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  7. Alaskandrummer

    Becky Administrator

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    Hey there, just wanted to say welcome to the forum :)
     
    Becky, Oct 24, 2016
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  8. Alaskandrummer

    Alchemy

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    If it works normally when holding down then I personally would have thought it was the switch itself or maybe I missed where you guys passed that.
    Also, I was told by a factory tech that power adapters will read much higher than their rated V until under the proper load after noticing all my power adapters read high. For example he said they use a 6V adapter for a 9V battery item which was surprisingly exactly what I had been doing and hoping to do. That item is fine from 0-12V however, it just doesn't work below 4-5V. If I remember, most of my 6V adapters put out around 9V and the 12V's put out maybe 15 or more but I forget on those. Power adapters do have issues of losing ouput over time and need replacing, maybe Gary knows why.
     
    Last edited: Oct 27, 2016
    Alchemy, Oct 27, 2016
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  9. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    Momentary power on buttons usually use a Flip Flop as a latching circuit.

    In this case a static discharge may have fried the chip.

    I'm dealing with a computer with this problem at the moment.

    Powers up for about 4 seconds then shuts down again.

    If it is the latching circuit on the MB I won't even bother repairing it. It's a 7 year old computer.

    Probably got fried by static discharge from a rug shock.

    Gary ;)
     
    happyrat1, Oct 27, 2016
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  10. Alaskandrummer

    Alchemy

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    You sound like you have the same kind of luck as me if that really did happen. That's about like exploding cell phones and static on gas cans. We should start a club. "Things that actually can happen." Recently I've been working on "brush fires caused by residual nitric acid from thrunderstorms" and "why not to use a vacuum pump for pressure" :)
     
    Alchemy, Oct 27, 2016
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  11. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    Actually a rug shock static discharge carries about 20 KV and can permanently take out a CMOS chip in a microsecond.

    Winters in Northern climates are especially nasty for that sort of thing.

    It's not at all uncommon up here in Canada and it happens hundreds of times every damned Winter.

    Some engineers take precautions in their designs to properly bleed off the voltage but more often than not when you go to hit a soft touch power button and feel a zap in your fingertip you stand a very good chance of blowing out the appliance.

    Gary ;)
     
    happyrat1, Oct 27, 2016
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  12. Alaskandrummer

    Alchemy

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    definitely new strides in use of the comment "everything you touch goes to ....." :D:D:D

    I briefly considered just now "hey now I can explain saying 'don't touch my car dude' " but around here I'd probably get punched :(
     
    Last edited: Oct 27, 2016
    Alchemy, Oct 27, 2016
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  13. Alaskandrummer

    Fred Coulter Collector of ancient keyboards

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    We had the opposite problem at Stetson University many, many years ago. There was a lightning strike on a different building. Enough of a charge managed to get across to the building with the Math Department that one of their Macintosh computers got damaged. No, not the way you're imagining. It wouldn't turn off.

    Turning off a Macintosh at the time -- perhaps it's changed -- was a software process. You selected turn off on the menu, and then the computer closed the files, etc. When it was good and ready, it would turn itself off. There was no power switch that you could manipulate. They ended up unplugging it whenever they wanted it turned off. A very low tech solution. (I've been known to remove batteries from laptops that freeze, but they work the next time.)
     
    Fred Coulter, Oct 27, 2016
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  14. Alaskandrummer

    Alaskandrummer

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    Well that's interesting. I ordered a new power supply so we'll see if that's it. Like I said I haven't found any visible damage on the PCB, and I would expect some black spots if it were damaged, but I'm sure that's not always the case. And yeah the power button is a momentary contact so I should be able to release it. Holding it down just basically bypasses the hold in circuit.
     
    Alaskandrummer, Oct 28, 2016
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  15. Alaskandrummer

    happyrat1 Destroyer of Eardrums!!!

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    Problem solved.

    The handyman's secret weapon :D :D :D



    Gary ;)
     
    happyrat1, Oct 28, 2016
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  16. Alaskandrummer

    Alchemy

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    not sure about the duct tape but the 3M electrical tape I just bought is fantastic
     
    Alchemy, Oct 28, 2016
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  17. Alaskandrummer

    Rayblewit Love Music / Love Life

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    I like that guy. he doesn't have square balls!:p
    The video is fascinating.
    I love seeing how things are made.
    To be honest . . "production lines" is my busines. I design and build packing line and processing line conveyors for every kind of industry.
    Just love chocolate factories and breweries the best.:rolleyes:
     
    Rayblewit, Oct 28, 2016
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  18. Alaskandrummer

    Alchemy

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    You would surely straighten out my place of work since everything is custom and makeshift. I have worked at two production line places years ago and the machinery is fascinating, yes. I love buying from closed factories for parts to build various monstrosities. :D
     
    Alchemy, Oct 28, 2016
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