List, I asked Brian DeTar to describe the procedure that Yamaha uses. Evidently, there was a series of articles in the Journal about it that I somehow missed. Anyway, here's what he wrote me with permission to post it to the list. It may be a little long for some, but maybe it'll be worth it. Avery =================================================================== BEDDING THE KEYFRAME By Brian De Tar PARTS/SUPPLIES RE-QUI-RED: None TOOLS REQUIRED: Long (12") Phillips or straight screwdriver Glide bolt wrench TIME REQUIRED: Approximately 10-20 minutes -- ONWARD -- Welcome to the first of a three part series on bedding the keyframe. I will explain a very simple procedure that I learned, while working with Yamaha, to establish the foundation from which all other action regulation will be built upon. Included in this series are some special notes to keep in mind when working with Yamaha Disklaviers. I believe we can all agree that, in order to achieve stability and consistency in action regulation, we must first establish a solid foundation. Some of the ramifications of an improperly bedded keyframe are: excessive action noise, loss of power and dynamic range, poor tone quality, inconsistent hammer height, let off, checking and repetition, and an action that "fights back" or feels "spongy" to the pianist. In the Yamaha Disklavier, a solidly bedded keyframe is also critical to ensure accurate playback of recorded material. Although this procedure can be used on most grand pianos, it was primarily developed for high quality, relatively flexible keyframes. Some of the manufacturers that use relatively flexible keyframes are Yamaha, Kawai, Steinway (with Kluge keyframes), Bosendorfer, etc. Ah, yes, you've probably heard "cheap" or "flimsy" or "cost cutting" in conversations about "flexible" keyframes so let's nip that in the bud and explore why it might actually be advantageous to have a relatively flexible keyframe. Using a relatively flexible keyframe makes it possible to easily adjust each glide bolt so that it supports the keyframe with exactly the same pressure as its neighbors. This allows the shift lever to operate much more efficiently and with less wear on the keybed. It also enables the technician to slightly increase or decrease aftertouch very quickly and precisely. This aspect alone is worth its weight in gold. How nice it is to be able to "customize" the aftertouch "feel" of a piano to accommodate the different tastes or familiarities of individual pianists. So next time we hear someone make a questionable remark about why a manufacturer chooses a particular path, we might look at it from a "solution" perspective rather than a "cost cutting" perspective. To have a concept of the "Big Picture", let's quickly outline the steps we will follow to achieve our goal. On Disklaviers: 1. Turn off the power at the control unit, and/or unplug the Disklavier from the wall 2. Remove the control unit (except "Wagon Grands") 3. Remove the fallboard, cheekblocks, and keyslip 4. Disconnect the keyboard connector (bass end on "Wagon Grands, treble end on all others) 5. Slide the action out 6. On Disklavier "Wagon Grands", remove the hammer sensor rail 7. Proceed to step 3 below On all others: 1. Remove the fallboard, cheekblocks, and keyslip 2. Slide the action out 3. Loosen the action bracket screws approximately 1/4 turn 4. Tilt the action up and turn the hidden glide bolts approximately 1/4 turn clockwise 5. Slide the action back into the piano 6. With the action in the piano, use a long screwdriver to tighten accessible action bracket screws 7. Slide the action out just far enough to tighten the remaining action bracket screws 8. Slide the action back into the piano 9. Check key height and key dip 10. Check for any "knocking" glide bolts and consistency in glide bolt pressure with the "Lift and Tap" method 11. Adjust the glide bolts 12. Adjust the (2) hidden glide bolts 13. Tap along back rail and check for any "knocking" against the keybed Tap along front rail and check for any "knocking" against the keybed Recheck for consistency in the glide bolts with the "Lift and Tap" method Replace the case parts and screws (and control unit on Yamaha Disklaviers) Pretty straightforward, isn't it? After a couple times through, you will be an expert. You will find it's quick, easy and VERY accurate! It's one of those many things that take longer to think about doing it than it does to "Just Do It"! Next month, we'll dissect each step and get to the "nuts and bolts" of bedding the keyframe. We'll delve headlong into what to do and, more importantly, some of the rationale behind WHY we do it. So, until next month, here is your first "De Tarism": "What you lose by NOT trying something is SUCCESS"! Now, take this article and go to your nearest grand. Once there, play around with some of the steps to see where you think we might be going next month! With a bit of practical exploration mixed in with a generous helping of curiosity, and a smidgen of anticipation, you will arrive next month with a fine recipe for optimal learning! Another helpful trick is to take all the steps above and draw them in diagram form. This is called "Mind Mapping" and brings into play several different parts of the brain to facilitate the learning process and retention in memory. Try it... It just might surprise you! -- ONWARD & UPWARD -- Well here we are again. It's great to see you back! Did you play around with any of the steps from last month? Did you create your own "MindMap" to help you remember the steps? If you did, way to go! Maybe some of you would be willing to share your MindMap with us. If you didn't create the opportunity yet, your adventure still awaits you! As promised, this month we'll discuss each step in detail. Remember: it'll take much longer to read this article than it will to actually do the work! PROCEDURE: ON YAMAHA DISKLAVIERS: 1. Turn off the power at the control unit, and/or unplug the Disklavier from the wall. This will prevent electrical damage to you or any of the components. I certainly don't want anything to happen to you, I still have one more article in this series for you to read! The power switch is located on the control unit. 2. Remove the control unit. The control unit must be removed to gain access to the treble end cheekblock screw. To remove it, simply remove the four screws (two on each side) from the control unit bracket. On MarkII grands, it's not necessary to remove the bracket itself. On MarkIIXG grands, the bracket and control unit are removed as a whole by removing the one screw located on the left side of the bracket and merely loosening the two screws located on the right side of the bracket. When this is done, slide the bracket/control unit forward and down to remove. 3. Remove the fallboard, cheekblocks, and keyslip, not necessarily in that order! Nothing new here, we do it the same way we always do! 4. Disconnect the keyboard connector. This is done by spreading the "ears" of the connectors outward toward the sides and gently pulling the connector out. The connector is located in the action cavity and is mounted to the rim on the bass end of "Wagon Grands, and the treble end on all other models. 5. Slide the action out. Please, oh please don't break off the first and last hammers! 6. DISKLAVIER WAGON GRAND ONLY: The hammer sensor rail must be removed to gain access to the glide bolts as well as have access to the bottom of the hammer rail. This is due to the circuit board attached to the hammer sensor rail. To remove the hammer sensor rail, first unplug the connectors located on the bass and treble end of the hammer sensor rail. This is done by spreading the "ears" of the connectors outward toward the sides and gently pulling the connector out. Next, locate and loosen the screws in the "keyhole" on the hammer flange rail. Next locate and loosen the screws holding the other side of the sensor bracket. They're located on the hammer side of the action brackets by the wippens. Make sure the "platform" that these screws go into do not turn when you loosen the screws. If they do, simply tighten the small (7mm) nut located at the bottom of these platforms. After the screws are loose, lift the key side of the hammer sensor rail slightly, it can now be lifted free of the action. Set it somewhere safe...we don't want it to get bent! 7. Proceed to step 3 below: ON ALL OTHER NON-PLAYER GRANDS: 1. Remove fallboard, cheekblocks, and keyslip. Same way we always do! 2. Slide the action out far enough to gain access to the action bracket screws. 3. Loosen the action bracket screws approximately 1/4 turn. Loosen the angled screws on the front center action brackets FIRST, and then loosen the remaining action bracket screws. Listen for a little "click" when you loosen these screws. This verifies that the keyframe has expanded or contracted a bit from changes in humidity, or was not on the keybed (or other "flat" surface) when the action bracket screws were tightened. By loosening and then later, tightening these screws in the piano, we eliminate any "flex" or tension between the keyframe and action stack. 4. While the action is still out, lift it up to gain access to the hidden (if present) glide bolts located on the underside of the keyframe. When lifting the action up, be careful not to scratch the stretcher with the drop screws! Turn the hidden glide bolts approximately 1/4 turn clockwise to raise them out of the way. This allows you to adjust the primary glide bolts without interference from the hidden glide bolts. 5. Slide the action back into the piano. Always make sure you lift the front of the keyframe slightly when placing the action back in the piano. Because the glide bolts extend past the bottom of the keyframe, they can gouge the front of the keybed if you're not careful. By placing the action back in the piano with the bracket screws still loose, the keyframe is allowed to conform to the keybed. If the action bracket screws are tightened when the keyframe is not being supported evenly, there is a probability that the keyframe will be locked in a position that is different than the keybed. This makes solid bedding difficult, if not impossible. This condition can also be caused by changes in humidity. 6. For this step, you will need a long screwdriver (approximately 12"). You can find a screwdriver of this length at Sears and many Home Depots. Snap-On also has one that works, but they can be hard to locate! Tighten all the accessible action bracket screws. With the action IN THE PIANO, insert the screwdriver between the string unisons down to the screws in the action bracket. You can reach most of the rear screws as well as, on larger grands, 1 or 2 of the front screws in the bass section. 7. Slide the action out just far enough to gain access to the remaining screws. Remember to tighten the angled, locking screws (keyboard side of the action) last. Again, tightening the screws with the action in playing position insures that there is no flex in the keyframe, and that it is truly mated to the keybed. 8. Slide the action back into the piano. Again, make sure you lift the front of the keyframe slightly when replacing the action back in the piano! Well, I used up this month's space pretty quickly. We must be havin' fun now, right? Additionally, we have arrived at the point we've all been waiting for: Bedding the Keyframe. That is what we came here for now isn't it? A little "Cliff Hanger" here is healthy. Right? Why not take some time now and try out what you have learned so far? For those of you that did a MindMap, did the preceding information change what it looked like? Isn't it interesting how gaining new information has the ability to change or reframe our perspective of things? One of the most powerful aspects of "Being Human"! Next month we'll jump right in with key height and learn all about this "LIFT AND TAP" stuff, plus "The Rest Of The Story" (Paul Harvey). Then we'll send you on to the beginning of your next adventure, Bedding the Keyframe! Until then, a couple more De Tarisms to ponder: "Mistakes are nothing more than OPPORTUNITIES to do it DIFFERENT the next time!" "Mediocrity is cumulative, so is Excellence!" Oh, by the way, you probably should go ahead and put the action back in and button it up...wouldn't want to leave all that temptation around for the kids, now, would we?! See you next month! WRAP-UP If key dip or key height is incorrect the outlined bedding procedure will prove itself out by the fact that the keyframe will not bed properly. If the dip or height cannot be maintained within the proper range, the height will have to first be established by inserting or removing balance or front rail punchings. With a little practice, bedding the keyframe will take you approximately 10 to 15 minutes, allowing you to quickly give a pianist slightly more or less aftertouch. We hope you've enjoyed this series of articles on bedding the keyframe. In the months to come, we're working on articles discussing many aspects of regulation and refinement on the Disklavier as well as other topics. In no time at all you'll all be "Disklavier Dudes and Dudettes! Until later, have fun and we'll see you soon!
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