Sorvall RT/T6000D - Page 75

Repair
and
Replacement
SORVALL®
Centrifuges
b.
P.C.
Board
Replacement
Procedure
CAUTION
DO
NOT
turn
a
refrigerated
centrifuge on
Its
side.
Any
position
other
than
upright
may
cause compressor
damage.
1.
Unplug
the
centrifuge
power
cord.
2.
Remove
the
set screw
from the
door
release
knob
using a
5/64
inch
Alien
wrench.
3.
Remove
the
knob,
making sure
the
woodruff
key
remains
in
the knob
shaft.
4.
Remove
the
screw
below
the
release
knob
shaft.
5.
Remove
the
screw
from
the
top
of the
panel,
located above
the
TIME
control
knob.
6.
Gently
unsnap
the
panel
corners
and
the
hinged
panel
will
drop down.
CAUTION
When
the front
panel
is
open,
a piece
of
fishpaper or
equivalent
insulating
material
should
be
placed over
the circuit breaker
area
before
servicing.
Before
removing
connectors
P7, P8,
and
P9,
or
the
wires
from terminal
block
TB2
on
the Motor Controls
P.C.
Board,
be
sure
to
note
proper
orientation
of the
connectors
and wiring
location to TB2. Failure to
properly
reconnect P7, P8,
and
P9,
or
properly
reconnect wires
to
terminals
on
TB2
can
damage
the
P.C.
board.
7.
Disconnect
the
three
connectors
(P7. P8,
and P9) from
the
Motor Controls
P.C.
Board (larger board).
Before
removing
P9
It
may
be
necessary
to
remove
the
mounting screw securing
the
wiring
harness
in
place.
Then,
after
noting
proper
wiring
locations
for
reassembly,
remove wires
from terminal
block
TB2.
8.
Remove
the four
mounting
screws
that
secure
the
Motor Controls
P.C.
Board to
the
front
panel.
(If
you
removed
the
mounting
screw
securing
the
wiring harness
in
place,
step
7
above,
remove
the
remaining
three
screws.) Then,
remove
the
nut
and washer
securing
the
heatsink to
the front
panel.
Remove and discard Motor
Controls
P.C.
Board
with
heatsink.
9.
Modify connector
P8
as
follows
to
make
the
wiring compatible
with the
new
p.c.
board
(see
figure
5-16):
a.
There
are
two
coax
shields
attached
to
pin
9.
Locate
shield
for
the
conductor
attached
to
pin
8,
then
cut
shield flush
with
pin
9,
as
close
as
possible to wire
Insulation,
using
wire cutters.
b.
The
remaining
shield
(center conductor
is
attached to
pin
10)
must be
insulated
since
it
will
cany
+12 volts (this
conductor
goes
to
the
Imbalance
detector).
Insulate
shield with
electrical
tape.
5-32