Table of Contents
Advertisement
6.
Replacement
of
line
power
fuse F102:
A.
Once
the top cover
is
removed, F102
is
accessible
without removing
any
other
components.
B.
Remove
F102,
shown
in
Figure
5-1,
and
replace
it
with
a
1/8A, 250V,
3AG,
SLO-BLO
fuse
(Keithley part
number
FU-20)
for
standard
line
voltage
units.
Optional
line
voltage
units
with
90-110V and
190-210V
ranges,
use
a
3/16A,
250V
SAG
SLO-BLO
fuse
(Keithley part
number
FU-29).
7.
Replacement
of
current
fuse F101:
A.
Lift
the
calibration
cover, or battery pack,
off of
the
spacers
to gain
access
to
the
current
fuse.
B.
Remove
F101,
shown
in
Figure
5-1,
and
replace
It
with
a
2A,
250V,
SAG
fuse (Keithley
part
number
FU-131.
C.
install
calibration shield
or battery
pack
on
the spacers.
Be
sure that the
ground
clip,
shown
in
Figure
5-1,
is
positioned
on
the top
side of
the
shield
or battery
pack.
8.
Reinstall
the top
cover.
1.
Turn
off
the
power and
disconnect the
line
cord.
2.
Turn
the
Model 177 bottom
side
up and
loosen the four
screws
in
the
bottom
cover.
These
screws
are held
cap-
tive
by rubber
0-rings.
3.
Hold
the top
and bottom
covers together
to
prevent
their
separation
and
turn the
Model
177 over
to
normal
posi-
tion.
4. Lift
off
the top cover
and
the
calibration shield.
The
four
plastic
spacers
must
remain
in
place
on
the upright studs
projecting
through
the
main
printed
circuit
board.
5.
Set
the
BAT/LINE
switch
to the
BAT
position
shown
in
Figure
5-4.
Note
that
the
battery
pack
will
not operate
properly
if
this
switch
is
not
in
the
BAT
position.
6.
Remove
the fuse F301
on
the
battery
pack.
7. Install
the
battery
pack
in
the instrument
so
that
it
rests
on
the
plastic
spacers.
The
ground
clip
must
make
con-
tact
With the
upper
side of
the
battery
pack
plate.
8.
Carefully
align
the
battery
pack
plug
with connector PIOO^
on
the
circuit
board.
Push
the plug
firmly
onto
the connec-
tor
until
the
lip
on
the plug
engages
the
lip
of the connec-
tor to lock
the plug
in
place.
CAUTION
Make
sure the
connector
is
aligned
so
that
ail
pins
mate
properly,
otherwise,
damage
to
the
Model
177
and
battery
pack
will
result.
9.
Install
the
fuse F301.
Reinstall
top cover
and
secure
witf
four screws.
10.
Charge
the battery
pack as
described
in
paragraph
2-6.
Table
5-3.
Line
Power Checks
Step
Item/
Component
Required Condition
Remarks
'
1
S101
Line
Switch
Must
be
set to
105-125V
or 210-
250V
as appropriate.**
n
!
i
2
S102
LiNE/BAT
Switch
Must
be
set to
BAT
for
use
with
battery
pack.
3
F102
Line
Fuse
Continuity
4
P1007
Line
Cord
Plugged
into
live
receptacle.
5
Turn
on
power.
6
f5V
Pad*
-h5V
±5%
Output
of
VR101.
7
VR101,
IN
C120-
'f7V
minimum.
Output
of
CR103,
.
2200fiF
(
-h
input to
VR101.
:
8
+
15V Pad*
-I-
15V
±10%
Output
of
VR102,
9
VR102
IN,
C123-
+
17.5V
minimum.
Output
of
CR104,
470^F
(
-h
input to
VR102.
...
10
-15V
Pad*
-15V
±10%
Output
of
VR103.
1
11
VR103
IN,
C125-
-17.5V
minimum.
Output
of
CR104,
f"1
V
i
470/iF
(-)
input to
VR103
NOTE:
Hot
regulator
may
indicate
shorted
load.
^On
main
printed
circuit
board see
Figure
5-1).
**On
optional
line
voltage
units set
to 90-1
10V
or
180-220V
as
appropriate.
I
!
5
Advertisement
Table of Contents
