Sequential Pro One - Revision L0;L1 PCB Mounting Modification

8. Pull off all knobs.
9. Disconnect wheel connector at left of PCB. (When reconnecting, orient connector so
that the side in which you can see the metal contacts is visible.)
,'
10. Remove 9 screws holding PCB to top panel (there are two screws near the
transformer).
11. The PCB should now lift away from the top panel, If not, check that the GATE
LED is not stuck or cemented.
12. Set the PCB on insulation on the bottom panel, and reconnect AC and keyboard.
Switch power on and, if tuning, allow the instrument to warm up for at least fifteen
minutes before proceeding.
WARNING! LETHAL VOLTAGE IS PRESENT IN THE POWER SUPPLY AREA
ON THE PCB (IN EARLIER MODELS) OR ON THE BACK PANEL (IN LATER MODELS).
4-2 REV BION 1.01 1 - 1 PCB MOUNTING MODIFICATION
To adequately protect the power switch on early Pro-Ones, an additional bracket must
be retro-fitted to eliminate vertical movement resulting from PCB flexibility. Figure
4-1 shows four views of the modification. Order Bracket Kit SCI #Z-204.
1. Open the Pro-One and remove PCB as described in para. 4-1.
2. Drill two holes through PCB as shown in Figure 4-1A.
3. Attach bracket M-323. to PCB underside using two M-100 #4-40 x 3/8" (9,525 mrn)
screws, two M-141 starwashers, and two M-099 4-40 nuts as shown in Figure 4-18.
4. Install PCB into top panel, tightening the 9 screws.
5. Drill hole through back panel as shown in Figure 4-1C. (Be sure to remove all loose
metai.)
6. When fastening the top and bottom assemblies, first install M-089 Jj8-32 x 3/8"
(9,525 mm) screw as shown in Figure 4-ID. Then install the remaining seven chassis
screws.