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Rusty, Music Professional
Category: Electronic Musical Instruments
Satisfied Customers: 6059
Experience:  Sound Engineer, Electrical Issues, Tone Consulting
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My yamaha clavinova is seriously distorting, it gives an unwanted

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my yamaha clavinova is seriously distorting, it gives an unwanted sound and its too distorbing.
Hello, my name is Rusty. Is the demo song distorted as well?
Customer: replied 2 years ago.
Yes, it gives the unwanted sound as soon as the volume is move out of zero level.
Ok, and what is your voltage from the output of the pitch bender to the amplifiers? (the input to your amplifiers)
Sorry, forgot to mention, the input voltage to your amplifiers when striking a key.
Customer: replied 2 years ago.
Yamaha clavinova cvp 55 does not have pitch bend and I m yet to connect amplifier! Perhaps I do not understand u
It does, you're thinking of a jog wheel. The pitch bender circuit applies effects, such as sustain. It also contains the demo song and percussion. It's the small circuit just before the amplifier stage. Test the input to your amplifiers when striking a key, and tell me the voltage. It should be around .1 to .3vdc.
Customer: replied 2 years ago.
The sound from demo, style and keyboard is no longer coming forth, only the unwanted sound!
Oh, that's different. When you strike a key, is there any change?
Customer: replied 2 years ago.
I m not with the piano presently, if I will be at all that will be 2morrow! As soon as I test it I will get back to you!
I should be here. I can find the location of the fault with a few tests.
Customer: replied 2 years ago.
Alright! And I guess you are talking about the main amplifier on the power supply?
No, the one connected to the speakers, headphone jack, and aux outputs.
Customer: replied 2 years ago.
Ok! Striking a key or playing demo or style makes no difference, except more distorting sound, but I will test that u said 2morrow
Sounds good. Disconnect the tone generator from the pitch bender as well, I want to eliminate that as a problem. The signal goes like this:Key->tone generator->pitch bender->amplifiers.
Customer: replied 2 years ago.
Alright, will get back 2 u tomorrow!
Thank you.
No problem, I'll talk to you then.
Customer: replied 2 years ago.
Ok! My yamaha keyboard psr s900 sustains unecessarily?
We have to open another question since it's a different keyboard, site policy. Click here to start another question.
Customer: replied 2 years ago.
Customer: replied 2 years ago.
Goodmorning R.
Customer: replied 2 years ago.
Mine understanding is as follow;
Green board= main board
Board with the STK amp.= Power supply board
Small board connected to jack= pitch bender
Customer: replied 2 years ago.
Finally I notice, its only when I play demo, style or keys that the noise responds and @ time its the moment I move the volume!
That definitely sounds like the pitch bender has gone out, I fixed 2 Clavinovas on Saturday that had the exact same problem. I'm seeing more and more of these going out. The power supply is the one connected to the power adapter jack. The keys are attached to the pitch bender. The pitch bender goes to the amps. It's the small board with a bunch of resistors and a few ICs.
Customer: replied 2 years ago.
Did u get the picture I attached initially?
Then, the keys cable is directly from key section to the main board and the small board with bunch of resistors and mini amp is where we have volume control cable connected to. If its the same board what can we replace? For the pre amp on that board is functional!
It's not the preamp, it's the resistance on the output. That's why it sometimes reacts when you turn up the volume, it sends a jolt to the amplifiers. I did not get your picture. Test the output resistors, I believe the problem is there. You can order the entire PCB from Yamaha, click here to find your nearest dealer.
Customer: replied 2 years ago.
Alright, I will do something about that and get back to you, if I know the exact time you will be available next from now I will so much appreciate. We are already @ night here.
It's nearly 2 pm here, I'm usually here between 10am and 6pm, sometimes pausing to run errands. Basically, if I don't reply right away, I'll be back shortly. Don't worry about the resistors in a row, those are for actually bending the pitch. Test the ones that are near the connectors. Also test the caps, and make sure they are working at the values written on them. Here is a resistor chart to help you: Click here.
Customer: replied 2 years ago.
Its somehow difficult to order the PCB here has the brand was never sold new, but imported as used! I will not mind any possible personal assistance! Perhaps it does not work out @ the end.
You'll find that the pitch bender, the one that does all of the stuff, is pretty simple... It's the least complicated board in the entire piano.
Customer: replied 2 years ago.
Alright, which of the IC in particular does that? I will get to work 2morrow and feed u back!
Thank You...
We don't need to mess with the IC, we can't get those anyway. Just focus on the resistors and capacitors.
Customer: replied 2 years ago.
Fine. See you 2morrow!
Customer: replied 2 years ago.
Those resistors are pretty good, having carefully measured! What next boss?
How about the caps? Are they at their values?
Customer: replied 2 years ago.
Yeah! They are.
Ok, disconnect the tone generator from the pitch bender. Is the noise still there? I want you to do the process of elimination on all of the boards connected to the pitch bender.
Customer: replied 2 years ago.
I have already done that and the noise was gone, but the piano brings forth no sound except a sound of an opened jack! I guess u understand?
Ok, disconnect the tone generator and play a demo song. How is the sound?
Customer: replied 2 years ago.
I have already done that, the noise was gone and yet no music sound generated except sound of open jack! I guess u understand?
Ok, now test the leads from the tone generator. Is that producing noise? Press a key and test as well, just to see the difference.
Customer: replied 2 years ago.
It gives sounds like when a jack is open and not yet plug in on a mixer!
The DCV from the tone generator, how many mV are you reading when a key is not pressed? How about when a key is pressed?
Customer: replied 2 years ago.
I guess the msg is mixed up due to some delay in network. The last test I carried out was that I disconnected the tone generator from the pitch bender and it gives a sound of an opened jack( sounding like the amp is opened to nothing) and the said piano is in mine office & I m presently @ home 11 pm here! Kindly explain the said lead as we got diff. Name we call those stuff here? Lead & mv
The plug that comes from the tone generator. I want you to test the millivolts to see if the noise is coming from the tone generator, or if it only gets introduced when plugged into the pitch bender.
Customer: replied 2 years ago.
First, I appreciate this slow & steady conversation due to the unsuitable time and the position of the piano!
My check simply shows again, when I removed the lead from tone generator, the unwanted sound was gone, even when a key is pressed or demo is being played. Only a sound of an open amp or jack. While the demo is playing/ when keys are played the lead measure 7.1 and 11.8 from 4pin & 6pin respectively!
And I notice the volume control couldn't control the said open sound.
Ok, and what about the voltage when a key is NOT played?
Customer: replied 2 years ago.
No diff.
Ok, that's your pitch bender. At this point we're chasing our tails, it will need to be replaced. Call Yamaha to order a pitch bender, those go out all the time. 0844(###) ###-####
Rusty and other Electronic Musical Instruments Specialists are ready to help you
Customer: replied 2 years ago.
Ok! I will get back to you.
Thank you
Customer: replied 2 years ago.
Just to inform you that my calls to the number you gave me isn't getting true since & I am planning to replace the two to three ICs on the board as it has already been condemned, while I still put calls across to the number. Honestly I will appreciate if I can simply get cost & possibly get the board from your end in order to hasten the process!
Thank you!
Unfortunately we don't sell products here, we just offer the advice. Are you saying that the number isn't producing good results? There's a guy in the UK named Mike Barden, give him a call. He fixes keyboards and organs, and can most likely expedite the process. Call 01483 236161. He's out until the 23rd helping his wife with her broken hip, but that's the guy to contact in the UK.
Customer: replied 2 years ago.
Ok, I will give that a try & am sorry for mike's wife condition!
But I will like to know if you practically repair or if its only here u didn't!
I'm sorry, I don't understand your question. Mike should be able to get you a new pitch bender circuit. Don't bother replacing the ICs, it's not worth it. Just replace the whole board.
Customer: replied 2 years ago.
I got that right!
I just want to know if you work on faulty instruments (electronic) practically? Trying to justify your experience!
Well I didn't get verified without experience. I help people with Clavinovas nearly every day. How would I know about Mike Barden in the UK if I this was my first time? I'm a busy guy.
Customer: replied 2 years ago.
Your experience is highly professional and I wonder if that could be possible without being practically in practice!
Customer: replied 2 years ago.
While I 'm waiting for Mike to resume on Monday, I will like to know if the pitch bender of CVP 55 is the same with that of CVP 35? I have access to a CVP 35 that works fine and I will like to test the bender if its the same or work for each other!
That is a question for Yamaha, call 0844(###) ###-####
Customer: replied 2 years ago.
Ok! Only that the number is ***** just connecting here, I will wait for Mike.
Sorry I can't help you there, I always call Yamaha for part numbers. Mike will know. In the meantime, if they look similar, and get the same voltage from the power supply, then it will work. Be sure to check the power and connectors before energizing the circuit.
Customer: replied 2 years ago.
Customer: replied 2 years ago.
I guess Mike is not yet back, I have called him severally this morning and just this afternoon and he's not picking his call, so I drop a message hoping he will respond soon! So also Yamaha Uk.
Customer: replied 2 years ago.
I just got through to Yamaha uk. Now and I was told the piano is out of stock and the pitch bender is not available! Except I go for second hand! How can you help out, Mike is not back yet!
If Yamaha isn't carrying them anymore, Mike is your best bet. If you send him the pitch bender, he will do his best to fix it. He's a busy guy, he's basically the UK piano guy. I suggest you look for a parts keyboard on, or call him again next Monday.
Customer: replied 2 years ago.
I'm a registered buyer on Ebay and I have searched the platform as well, I will try Mike again! Thank you!!!