Table of Contents
Advertisement
Thermo Scientific
*** Problem G: Motor Speed Erratic or Fully on (continued) ***
3. Check Optical Sensor. Just as the Optical Disc can be dirty, the lenses of the
optical transmitter and sensor can also accumulate dust and dirt. It would be
good practice before making the following voltage measurements to be sure
these lenses are clean. The lenses are located on the inner walls of the sensor.
a. Connect the negative lead of a DC voltmeter to TP1-COM on the CPU
board.
b. Connect the positive lead of the DC voltmeter to the lead of R4 which
is closer to the edge of the circuit board.
c. Turn the bath power "ON" and the motor "OFF".
d. Turn the optical disc slowly by hand until a dark portion of the disc is
centered between the optical sensor. The voltmeter reading should be
greater than 4 volts DC.
e. Repeat Step D so a clear portion of the disc is centered between the
optical sensor. The voltmeter reading should be less than 1 volt DC.
f.
If the last two steps did not read correctly, then replace the optical sensor.
4. Check Display Board #3176679; Problem F, Step 6.
5. Check Power Supply Board #3166924; Problem F, Step 7.
Troubleshooting Section 10
Reciprocal Shaking Water Baths
10-9
Advertisement
Table of Contents
