General Descriptions; Qs6 - Alesis QS Series Service Manual

1.00 General Descriptions

The QS series of 64 voice, keyboard and rack mount digital synthesizers represent the
current state of the art in high end digital synthesizers. It is certainly recommended that
technicians be thoroughly familiar with the operation of the units according to the User's
Reference Manuals before attempting any repair. As is often the case when machines present
the user with so many options, many "repairs" can be made simply through education in the
correct way to use the product. The software histories in Appendix B of this manual may also
prove to be an excellent aid in troubleshooting User difficulties.
Several of these units utilize the same PCBs. For example, the QS7 and QS8 have
identical main PCBs, and all three keyboards (QS6, QS7, and QS8) use the same keypad
PCB. However, some PCBs may be different between individual units while performing similar
functions. In order to minimize confusion between reference designators for the different unit
types, the following conventions will be used throughout this manual:

1.10 QS6

With the release of the original S5 (later updated to S5+ A.K.A. S9) QuadraSynth
keyboard and the S4 (later S4+ or S8), Alesis jumped to the forefront of a field in which it had
no previous experience. Since then, we have learned a great deal about the construction of
keyboards, as well as the needs of keyboard players in general. This inevitably led to the
release of the QS6. Smaller, lighter, and with improved sound quality, the QS6 was an instant
success. Still minor improvements have been made through the lifetime of this which have
resulted in several main PCB revisions. Each revision incorporates previous changes as well
as any new improvements made. These changes are outlined in Appendix A. This manual
references the following schematics and component I.D.s unless otherwise noted:
Refer to Figure 1 for a simplified view of the QS6's electronic systems.
Alesis QS Series Keyboards Service Manual V1.00
QS6 Reference Designators are BOLD (e.g. R6, C9)
QS7 Reference Designators are Italicized (e.g. R6, C9)
QS8 Reference Designators are Underlined (e.g. R6, C9)
QSR Reference Designators are Plain (e.g. R6, C9)
Combinations are allowed (i.e. Italicized and underlined indicate both
QS7 and QS8 references) (e.g. R6, C9)
PCB
Main
Slider
Keypad
Schematic Revision
S6 B
S6 B
QS6/7/8 C
1
11/19/06