Greetings Julien,
I live in a remote location in the US where it is virtually impossible to get decent help with anything. I therefore am often forced
to learn how to diagnose and fix things myself that are best left to the true experts. For example I just restrung one of my pianos
and that was an experience :) So here is a suggestion that I would not make to anyone who could easily get a good Disklavier technician.
I am not familiar with the way the DKV pedal works but am very experienced with all sorts of electronic and electromechanical
devices. Someone who does know that way the pedal works on your model of DKV may be able to make additional suggestions.
Diagnosing any problem like this is best started with simple tests to determine the range of the problem or the approximate location
or cause. The solenoid is electromechanical and can have problems in the electrical area or the mechanical. I am not specifically
familiar with the way the DKV pedal works but it is likely to be controlled with a modulated voltage and a position sensor. If the
position sensing is not working it may be trying to work too hard. If there are mechanical problems such as a sticking solenoid plunger
or a stiffness in the pedal mechanism itself this could also cause overheating. It is unfortunate that the pedal mechanism is so
under-designed. A solenoid such as this should never even get close to warm working all day. My LX piano solenoid warms about
10 degrees if playing for 5 hours and has enough power to lift the piano off the floor not just the damper tray.
For a first test, try to move the dampers yourself by hand from a position close to the solenoid. Dampers on a grand should not require
Herculean force. Does it feel smooth or is there a catch or stickiness at any point. Can you easily move the damper lifting components as far
as they would be lifted by full motion of the solenoid, without any stickiness. If there is any binding there is something wrong with the
damper mechanism. It is possible that something is too tight, out of position or may have been blocked for protection in shipping.
Remove the load from the solenoid by moving or disconnecting the damper mechanism from it so the solenoid is free to move just itself.
There should be a built in limit to full travel so it should be OK to play the piano without lifting the actual dampers. If there is no stop
(difficult to imagine that Yamaha would not have one) then it would not be a good idea to play the piano with the dampers disconnected.
Try playing just a short section with pedaling to make sure that playing with a disconnected damper does not cause slamming that may
damage components. If all seem fine try playing a bunch of music (with ear plugs) and see if the solenoid overheats.
If the solenoid slams when playing disconnected it may be that a position sensor is out of alignment blocked or disconnected. Look
for such a device which may be either a simple optical switch or a position encoder. There should be an obvious flag or scale that
runs in an optical sensor. Anything that is bent broken or a wire that is disconnected may cause the sensor to malfunction but it is
difficult to imagine that the Disklavier is not designed to give an error message if something is wrong with a critical system such as this.
If the solenoid does not overheat with the load disconnected the problem is most likely excessive loading of sticking within the solenoid
itself. It is possible that it will move smoothly without a load and then sticks under load only. Disassembling and or lubricating the
plunger is best left to someone who understands electromechanical devices. Any good technician who understands things like
computer controlled machines in general should be able to at least figure out where the problem is, if you can not get a DKV tech.
Wednesday, May 20, 2009, 2:16:59 AM, you wrote:
I leave in Albania where is only one disklavier. The official local rep of YAMAHA is a very good person, I bought the grand piano through him, waiting months for delivery, but he knows nothing about disklavier. I have it now brand new for 3 months and this problem of pedal was from the first day.
As far as I see you are located in London. I am ready to pay a round trip ticket LONDON TIRANA (British Airways has direct flights) + hotel and accomodation for an excellent specialist to solve my pedal problem definitively... This morning the pedal stopped working after 51 minutes. Temperature of room is 22°C and humidity is 55% . I care about humidity because my residence is 75 meters in front of Adriatic sea but I use dehumidification system.
From: athomik
To: disklavier@yahoogroups.com
Sent: Wednesday, May 20, 2009 10:47:49 AM
Subject: Re: [disklavier] Pedal problem Disklavier Mark IV (excessive heat)
The pedal should work fine playing all day. There is obviously something wrong with this pedal.At this point, I would get a technician to have a look at it.
athomik
On May 19 2009, Julien Roche wrote:
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>Were about 6mm play in the loud pedal that I adjusted to zero with the upper gold colored screw and the stroke is reduced from 15,51mm to 9,75mm according to calibration procedure of Service Center.
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>Now the pedal is stopping working (too hot, protection working) after 1h15mn of normal piano playing. It is normal ?
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>If yes, what do you think with very low noise external forced ventilation as the radiator looks under designed, same size as for the other pedal, which is not working so much and stayed reasonably low in temperature, they have the same size which looks strange in design.
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>If no, any additional sugggestion ? Thanks.
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>____________ _________ _________ __
>From: athomik
>To: disklavier@yahoogro ups.com
>Sent: Tuesday, May 19, 2009 12:51:37 PM
>Subject: Re: [disklavier] Pedal problem Disklavier Mark IV (excessive heat)
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>If the lines on the pushrods line up as per the instructions inside the solenoid cover, and there is no excessive play in the rod (try shaking it side to side), then the overall geometry of the pedal/pushrod/ damper lever is not correct. This would be a job for a piano technician. If you do get play in the pushrod (at the bottom of the solenoid), there are two gold coloured screws at the top andbottom of the solenoid which can be adjusted. They should be in a position where you just remove the play in the push rod. If the screws are too tight, the solenoid has to work overtime, which can cause overheating.
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>gher than edge line F when the loud pedal is fully depressed.)
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>>Maybe solenoids adjustments ?
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>>Great thanks for your help !
>>Julien
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>>____________ _________ _________ __
>>From: athomik
>>To: disklavier@yahoogro ups.com
>>Sent: Monday, May 18, 2009 12:11:05 PM
>>Subject: Re: [disklavier] Pedal problem Disklavier Mark IV (excessive heat)
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>>The pedal should not need any extra cooling. You need to make sure that the pedal is properly set up (get your technician to check) and the solenoids need to be adjusted properly. Once everything is physically OK, you need to run the pedal calibration procedure from the Service Center. I have come across this several times, and every time it was down to the fact that the pedals haven't been re-calibrated after the lyre was re-attached.
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>>athomik
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>>On May 18 2009, julien.roche@ ymail.com wrote:
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>>>Hi,
>>>
>>>Again problem with my grand piano that stops right pedal working after about 40 minutes of normal work because of overheating protection.
>>>
>>>Anybody has suggestion ? Tuning of pedal is ok. Maybe adding ventilators to cool the metal box on top of pedal ? Radiator is terribly hot.
>>>
>>>Thanks
>>>Julien
>>>
>>>
>>>
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