Hach DR300 Service Manual page 38

Repairs
Step Description
3 Remove the plastic insert for dongle or the Hach
Communication Dongle.
4 To remove the screws (4x), use a TORX T10 torque screw
driver.
5 Open the instrument.
1. Top housing including keypad
2. Display
3. Mainboard including optical unit
4. Seal
5. Bottom housing
6 To reassemble the instrument, follow the previous steps in
reverse order.
Note: Coat the seal groove with Krytox oil.
Note: Make sure that the seal is in the correct orientation.
Note: Make sure that the screws are tightened to 0.8 Nm.
36
Picture