42
Troubleshooting Table Advanced
™
Osmometer 3250/Cryoscope 4250 Service Manual
Troubleshooting Table
Symptom Explanation Suggested Action
1. Abrupt loss of power
(no display)
Interrupted power connection or
loss of power.
1. Make sure the power cord is
firmly plugged into both the wall
outlet and the socket on the back
of the instrument.
2. Temporarily unplug the power
cord from its wall outlet and
replace it with a known workable
lamp or small appliance. Have the
power restored.
3. Measure the AC voltage supplied
at the power outlet used for this
instrument.
4. Unplug the power cord from the
power cord socket. Visually check
the fuses for a blown fuse. If there
is any doubt, test the fuses with a
continuity checker or ohmmeter
or simply replace them.
5. Check the values marked on the
fuses.
6. Replace blown or incorrect-value
fuses with time delay (T) fuses.
Refer to instrument serial number
label for proper fuse value.
7. If a fuse was blown and a
replacement fuse blows too,
contact our product service
department for assistance.
2. “A/D Init Failure”
“A/D High Filter Error”
“A/D Low Filter Error”
“A/D Cal Mode Error”
One or both A/D converters lost
initialization.
1. Turn power off and on.
2. If problem persists, replace
application board.
3. “Baudrate Error” The baudrate setting is out of range. Reset baudrate in SETUP menu.
4. “Block Probe Failure” The block probe has failed (usually
shorted).
Check the block probe resistance
(2,300 ohms ±300 at room temp.)
5. “Block Probe Open?” The block probe resistance is
greater than A/D converter can
measure.
1. Is the probe plugged in?
2. Check the block probe resistance
(2,300 ohms ±300 at room
temp.)
6. Buzz Point Default
Set
The freezing point setting was
outside the allowed range.
The default setting has been
automatically set.
1. For the 3250, use SETUP menu to
change, if desired.
2. For the 4250, this is a fixed value.
7. “Calibration
Cancelled”
The STOP button was pressed
during calibration.
Calibration cancelled.
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