Thermo Scientific 20 GENESYS, Service Manual

Page: 24 / 205

Troubleshooting
4 - 6
7. Common Problems and Probable Cause
The following is a list of problems which may be encountered in
servicing the GENESYS 20. The symptom is described in the left hand
column. A suggested action is listed in the right hand column. Items in
quotes "" are actual display texts.
Symptom: Possible Cause:
No Display 1. Display cable is not connected to
Main Board.
2. Contrast adjustment pot is not
turned fully counter clockwise.
3. Display cable offset on header.
(Pin 1 not aligned with pin 1 of the
header.)
4. Display is defective. Replace.
Limit switch error 1. Wires connecting limit switch to
main board are not connected
(check both ends of wire assembly).
2. Sector gear is not moving,
therefore not closing limit switch.
3. Limit switch is defective. Check
continuity of switch with an ohm
meter.
A/D Error 1. Hardware failure. Replace main
board.
Continuous Beep This can occur when lines on the
microprocessor data bus are held either high
or low.
1. Unplug Mono drive board data
cable (J16). Power up main board
with J16 not connected. If beeping
stops, there is a short in the mono
drive board, or the data cable (J16).