Du Pont SORVALL RC-5 Service Manual page 108

Sorvall®
CentrifugesDrive
System
CircuitTable
4-10.
Troubleshooting Chart,
Automatic
RateController
Sheet
4 of
4PROBLEM:
System remains
in slow
start;does
not
transfer to RUN.
Operatesnormally
in RUN
mode.System
Conditions:1.
SLOW switch
ON.2.
"SPEED"
control
set to
more than 1000
rev/min.3.
START
switch ON (START lamp
lit).4.
Door
closed.5.
RATE
control at maximum
setting.Check
tachometer
voltage
acrossR25.
At 1000
rev/min.
voltageshould
be 0.7 V ac which
shoulddouble
for each addtional
1000rev/min.
Is proper
voltagepresent?YESNORemove
power.
Check
continuitybetween
P109-6
and
terminal1021
on PC-50195, and
betweenP109-3
and terminal 1021
onPC-50195.
If open,
repair
orreplace
as
required.At
some
"speed"
above
1000
rev/min.check
for 0V across CR11.
Isvoltage
correct?0V12VdcReplace
PC-50155.Check
for
115 V ac
betweenterminal
701
on
PC-50195and
gnd.
Is voltage
present?0V115
V
dcReplace
K206.Remove
K206.
Check
for115
V ac
between pin
A
onrelay
socket
and
gnd.
Isvoltage
present?Remove
power
and
checkcontinuity
between pin
A
ofK206
socket and terminal
1007on
PC-50195.
If open,
repairor
replace as
required.8/79RCS/1524-27