Question about Roland Musical Instruments
Counting the keys from left to right, from switch on every third key won't work, run your finger up and down the keyboard and then three keys don't work out of every five, press lots of keys randomly and the left to right pattern is working, not not, working working working, not not, working, not not, working working working, not not, various numerical patterns of keys not working. The three tranistors on a heatsink in the power supply were all dry joints but soldering them didn't help.
The keys are scanned in a matrix. It sounds like two of the matrix lines are broken. They may be broken on the board which the keys contact. These are often conductive rubber "pills" pressed onto finger like patterns of circuit traces. The traces have a black coating in the contact area. If the keys have been "mashed", sometimes the board is cracked. IF the crack goes through one of these contact areas, that is fatal. That board needs to be replaced.
A loose cable where two wires of the matrix aren't contacting would do it as well.
Posted on Jul 29, 2009
Tips for a great answer:
Aug 17, 2015 | Musical Instruments
Jun 09, 2015 | Musical Instruments
Nov 21, 2013 | Casio 76 Key Smartmedia Keyboard
Sep 13, 2012 | Yamaha P-85 Electronic Piano
Aug 05, 2011 | Musical Instruments
Jul 26, 2011 | Yamaha Musical Instruments
Feb 10, 2011 | Casio Ctk 496 Electronic Keyboard with 61...
Jan 14, 2010 | Yamaha Full-Size Keyboard
Nov 17, 2009 | Yamaha Musical Instruments
Jul 14, 2009 | Casio Ctk 496 Electronic Keyboard with 61...
Jun 10, 2016 | Roland Musical Instruments
530 people viewed this question
Usually answered in minutes!