Table of Contents
Advertisement
SERVICING
MODEL 630 POTENTIOMETRIC ELECTROMETER
I
Difficulty
Probable
cause
Solution
eter
rattle,
drift,
or er-
is observed
on all
null
Excessive
drift
on most
sensitive
range
Line
voltage
variations
cause measurements
to be
out of specifications
Reference
voltage
supply
drifts
after
30-minute
warm-up,
requiring
frequent
adjusting
of the range
con-
trols,
R327, R334, R337 and
R339
Measurements
out of toler-
ance on all
ranges
Measurements
are out of
specifications
on one
range
other
than 500-
volt
range
TABLE 4.
Tube VlOOl,
V1002 or V1003
Check tubes;
replace
if
faul
is faulty
tY
-6v power supply
is drift-
ing or oscillator
circuit
is faulty
Check power supply
stability
PC104, and oscillator
fre-
quency
(paragraph
5-7).
If
I
faulty
component
cannot
be
located,
return
instrument
to
factorv.
Faulty
VClOl
I Replace
VClOl
Battery
BlOl
is
faulty
I Replace
BlOl
Tube V3005 is defective
Check tube;
replace
if
faul-
ty
V3001,
V3002, V3003 or
I
Check tubes;
replace
if
faul,
V3004 is defective
w
One of the divider
resis-
tors,
R325 to R330, is
changing
value
rapidly
dur-
ing warm-up
Return
the instrument
for
factory
check-out
Zener diode,
D302, is un-
I
Return
the instrument
for
stable
factory
check-out
Light
modulator,
F,302,
is defective
Out of calibration
Check light
modulator
by re-
placing.
Refer
to paragraph
5-5 for
recalibration
One of the divider
resis-
Return
the instrument
for
tars,
R325 to R330, is
factory
check-out
Resistor
in the range
di-
vider
network
is faulty
Paragraph
3-2 d points
out
the resistors
used for
each
range.
Try to bring
the
ranges
within
specifications
by calibrating
with
the po-
tentiometers
in the network.
See paragraph
5-5.
If
this
does not work,
check indivi-
dual
resistors.
(Sheet
1).
Model 630 Troubleshooting
18
Advertisement
Table of Contents
