Revision L0/L1 Pcb Mounting Modification - Sequential Pro One Technical Manual

8. Pull off
all knobs.
9. Disconnect
wheel
connector a t l e f t of PCB. (When reconnecting, orient connector so
that
t h e side in which you can see t h e metal contacts is visible.)
, '
10.
Remove 9 screws holding PCB to top panel (there a r e
t w o screws
near the
transformer).
11. The PCB should now
l i f t
away from t h e
top panel, If
not, check t h a t t h e GATE
LED is not stuck or cemented.
12. Set t h e PCB on
insulation on t h e bottom panel, and reconnect A C 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
O N THE PCB (IN
EARLIER MODELS) OR
O N 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 b r a c k e t
must
be retro-fitted t o eliminate vertical movement resulting from PCB flexibility. Figure
4-1 shows four views of t h e 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 F i g u r e 4-1A.
3. Attach bracket M-323.
to PCB underside
using two
M-100 #4-40 x
3/8" (9,525 mrn)
screws, t w o M-141 starwashers, and t w o M-099 4-40 nuts
as
shown in Figure 4-18.
4. Install PCB into t o p panel, tightening t h e 9 screws.
5. Drill hole through back panel a s shown in Figure
4-1C.
(Be sure t o remove all loose
metai.)
6. When fastening t h e t o p
and bottom assemblies, first install M-089 Jj8-32 x 3/8"
(9,525
m m ) screw as
shown in Figure 4-ID. Then install the remaining seven chassis
screws.