Yamaha 88 key piano grand plays wrong pitches w/ changing volume

SOURCE: Yamaha digital piano clp 170

This is a common problem with Yamaha keyboards. The problem is caused by worn-out rubber contacts in the keyboard assembly. In my old Clavinova CLP-500, there was one long rubber contact strip under the keys with two parallel strips of semiconductor material. The Clavinova circuitry determines key velocity by measuring the timing between when the key hits the first and second strips of semiconductor material. The harder you play a key, the less time it takes the key to hit the second semiconductor strip after hitting the first.
After years of playing the keyboard, the keys eventually cause tears in the semiconductor material and this messes up the timing measurement for key velocity. The only solution is to take the keyboard apart and replace the rubber contact strip with a new one.
I got rid of my CLP-500 four or five years ago and got a new CLP-170. The CLP-170 is now having exactly the same problem that the CLP-500 had. Yamaha has re-designed the rubber contacts in the CLP-170 so that there are now eight individual contact strips instead of one long one. The problem is essentially the same, though. You have to take the keyboard apart and replace the worn out rubber contacts.
Here are the part numbers for the rubber contacts that need to be replaced in the CLP-170: V8286600 Rubber Contact, 12 keys, D-C#   Qty. 6 V8286800 Rubber Contact, 11 keys, A-C#   Qty. 1 V8286700 Rubber Contact, 5 keys, D-C   Qty. 1
I suggest you also get a copy of the CLP-170 service manual, part number 001677. It has descriptions of all the steps necessary to take the thing apart and put it back together again. You'll also need a "rod" (which is just a long dowel), part number TX000670. Before you take the circuit boards off the keyboard assembly, you have to insert the dowel between the keys and the frame to keep the keys from falling back and getting in your way. A 5-foot long 1/4-inch dowel will probably work. (I haven't yet taken apart my CLP-170, and I don't have Yamaha's "rod," so I'm not sure if 1/4 inch is the right size or not. I'll report back here if it's not.)
Good luck, Howard

Scott Frye

• 1175 Answers
• Posted on Jan 12, 2009

SOURCE: Yamaha clavinova won't play C natural in any octave

Hi ...
There are flexible cables that connect the keys to the main electronics. The connectors for those cables sometimes age poorly..
It is fixable. But dont "get taken" on a repair.
If it's just resoldering a few points,it shouldnt be more than $100.00
to fix

SOURCE: YAMAHA TOUCH SENSITIVE 88 KEY ELECTRONIC KEYBOARD WITH USB

Try this link for user guide. Hope this helps.
http://www.yamaha.com/yamahavgn/CDA/Search/SearchDetail.html?selectContentType=-1&checkboxLegacy=on&selectSearchArea=-1&textKeyword=electronic%20concert%20grand&Submit=Submit