Archive of the former Yahoo!Groups mailing list: Yamaha CS80
Subject: Re: CS-80 tech question: initial velocity problem on TSB board
From: jonathan4051@...
Date: 2018-01-07
I checked the voltages at the 4051 key input pins (13-15, 1, 2, and 5), and they do not look reasonable. Whilst healthy keys on other 4051's rest at 6V and approach 13-14V as you apply aftertouch, the bad keys are resting at 9.23V and jump to 15.49V as soon as they are hit, without even applying the aftertouch. The voltages on some of them slowly drop back toward 9.23 until you hit them again and they jump back to 15.49V. Odd.