Basically, this is useful if you need to recalibrate your joystick centers and min/max values (If your DX7 was a bit off on the right stick, but now it's fixed without sending to the Vendor).
Power up the DX7 with SCROLL DOWN & SELECT pressed, use DOWN to get to Model Reset, DOWN & SELECT to enter the reset menu, use the AILE D/R Switch to toggle with the EDIT + & -. 5 Cycles takes you into the Service Menu.
Entering the menu gives you a Dark Screen (pixel test), Scroll Up gives you Switch Test, SCR UP then gives you Battery Alarm and Displayed Voltage, SCR Up then gives you Stick Centres ( Hex Codes), SCR Up then gives you Stick Calibration, use the CLEAR to save the data, use SELECT to select the stick being calibrated, SCR Up gives you "ALL Settings OK ? " press the CLEAR key for Yes.
Please check this out,
I've read some forum that it can change 9.0V alarm to 11.1V for Lipo battery used.
USE AT YOUR OWN RISK