Sequential Pro One - Revision 1.0;1.1 Power Connector Modification; Replacing and Adjusting Wheels

4-3 REVlSION 1,OJ 1 .l POWER CONNECTOR MODIFICATION
It also turns out that the original version of the Pro-One's power connector (to the
PCB) is not foolproof. Particularly because you can't see what you are doing when
you're reassembling a unit, it is possible to incorrectiy mate the female cable
connector to the male PCB deader by skewing the pins. This can result in applying one
side of the ac line to the Pfo-One's ground system. If the Pro-One happens to also be
grounded to external equipment through the AUDIO OYT connection, the resulting
high currents will destroy the PCB.
The problem is corrected by using a 5-pin female connector keyed at both ends, as
shown in Figure 4-2. If a 1.OJl.l Pro-One being serviced has either a 3- or 4-pin female
connector, remove them and install the 5-pin connector system (order SCI DZ-049).
With the 5-pin system it is still possible to reverse the connection, but this won't
damage anything.
Figure 4-2
REVISION E .O/l .l POWER CONNECTOR MODIFICATION
4-4 REPLACING AND ADJUSTING WHEELS
Whenever you open the case, inspect both wheeIs $or cracks which usually occur
perpendicular to the set screw. If you see a cracked wheel, replace it.
The PITCH and MOD wheel mechanics are basically identical, but they are trimmed
differently. To repair either wheel:
1. Open the Pro-One as directed above.
2. Inspect both wheels, but if both need replacing fix one completely first, then fix the
other. (SO you can have the other to refer to.)
3. Remove the wheel assembly (bracket] from the top panel by unscrewing the 6-32
hardware.
4. Look at the wheel assembly. The potentiometer rotation is limited by two molded
stops on the wheel. When replacing with a new wheel (SCI #M-3521, be sure the
limiting stops are correctly oriented.