Keithley 236 Service Manual

SECTION 3
Maintenance
3 If the
cooling
fan
needs to be removed,
proceed
as
follows.
Otherwise, proceed
to
step 4.
A.
Disconnect P22
(fan)
from
J22
on
the digital
board
(see
Figure
3-2).
B.
Disconnect
the
ground wire
from
the rear
panel.
c. Remove the
four
fasteners
that
secure
the fan
to
the rear
panel.
D Pull the fan
out
of
the
instrument
case.
4, For
the
Model
237,
remove
the
resonant
converter
board
(see
Figure
3-3)
as follows:
Note:
The
resonant
converter board
is mounted
on
the
digital
board. Figure
3-2 indicates
the location of
the
resonant converter board.
A. Remove
the
shield
that
covers
the
resonant
con
verter
board.
lt is secured
with
four screws.
B.
Disconnect P17 from
J17,
and
disconnect P23
from
J23
which
is
located
on the
digital
board
(see
Figure
3-2).
c,
Carefully
lift the
resonant converter
board out
of
the
instrument
case.
Note: When reinstaffing the resonant converter
board,
make sure
the
two cable
clamps,
which
protect
the
wires, are
installed
in
the
slots
of
the
shield.
5.
Remove the
output
board
(see
Figure
3-4)
as follows:
Note:
The
output
board
is
mounted
on the analog
board
adjacent to
the
rear
panel.
WARNING
To
avoid bums
from
excessive heat, make
sure that
the heat sink on the
output
board
is
cool enough to handle.
If the heat sink is hot,
wait until
it is cool
before
attempting to
re
move the
output board.
A.
Disconnect
P16
fromJl6
on the
digitalboard
(see
Figure
3-2).
B.
Remove
the
four
screws that
secure
the
output
board assembly
to
the
analog board.
c.
Grasp the
heat
sink and
lift up
the
output
board
assembly
a
few inches.
Disconnect P15 from J15
which is
located on the analog
board
directly
un
der the
output
board.
D. Lift the
output
board out
of the instrument
case.
J17
Figure
3-3. Resonant Converter
Board
(Model
237)
(Shield Removed)
3-5

Keithley 236 Specifications

General

Brand	Keithley
Model	236
Category	Measuring Instruments
Language	English