Application Note

Regenerating the ST-4/ST-4X/ST-5/ST-5C Desiccant

This Application Note describes the procedure for regenerating the desiccant used in the ST-4, ST-4X, ST-5 and ST-5C cameras.  The purpose of the desiccant is to absorb the small amount of moisture in the air within the CCD chamber so that no condensation will form as the CCD is cooled.

Removing the Desiccant

Using a phillips head screw driver, remove the four screws that hold the nosepiece onto the camera body and set the nosepiece, screws and O-ring aside.  Carefully remove the desiccant, which is a "coffee" colored ring, from around the CCD by lifting it up from the camera.  Pay attention to the rather delicate wires connecting the CCD to the preamp board.  You may want to replace the nosepiece while the desiccant is "baking" to prevent dust from settling inside the CCD chamber.

Regenerating the Desiccant

The desiccant can be regenerated by heating it in an oven at 400 degrees Fahrenheit for four hours.  Do not heat the camera, only the desiccant ring.

Reassembling the Camera

Carefully place the desiccant ring over the CCD and roughly center it.  At this time you should clean the CCD and nosepiece window of any dust that may have settled.   Use a soft brush of Q-tip to wipe the surface clean, and being careful not to damage the delicate wires that connect to the CCD.  You may find dampening the Q-tip with Isopropyl Alcohol helps remove persistent dust or water marks.

Make sure the CCD is clean and dry and then reattach the nosepiece, paying careful attention to make sure the O-ring is properly seated and the desiccant ring is not pinched.  After reassembly the camera let the camera for 15 minutes before powering up.  This will allow the desiccant to absorb the residual moisture.