Replacing Gray-Scale Hammer / Key Shutters - Yamaha disklavier IV / Pro Series Maintenance Handbook

7. Replacing gray-scale hammer / key shutters

Gray scale shutters replacement
Since both gray scale hammer shutters and key shutters are optical transmission type, replace-
ment might be necessary when there comes an error message with certain key numbers dis-
played during sensor calibration. Some of them might have optical transmission problem and they
might be dusty or broken for some reason.
* Key gray scale shutters
Key shutter is the assembly of white shutter base block and gray scale shutter.
Gray scale shutter is provided as service part WC368200 ( 1 / piece)
* Hammer gray scale shutters
Hammer shutter is glued on the side of the hammer shank. When you replace it, there are guide lines for both
vertical - hammer roller butt plate, and horizontal - upper edge of hammer shank.
See the drawing as shown at right bottom. Service part - WE105700 ( 4 / set)
Be careful to avoid getting fingerpronts on the shutters !
Execute piano calibration (Full) after replacing shutters. See 6-4. bottom.
* Shutter replacement procedure
KEY SHUTTER KEY SHUTTER
KEY SHUTTER KEY SHUTTER KEY SHUTTER
REPLACE
SENSOR MEASUREMENT IN THE SERVICE MAINTENANCE MODE ‑ PIANO CALIBRATION (FULL)
HAMMER SHUTTER HAMMER SHUTTER
HAMMER SHUTTER HAMMER SHUTTER HAMMER SHUTTER
REPLACE
MHB23 MKIV/PRO DIOV1.05, SCV.1.01 PAGE.24