113
Maintenance
9.11 Motor/gear box
The motor/gear box requires no regular maintenance. The special formulation gears are
self lubricating and require no oil or grease.
9.12 Internal desiccant module
Note: The desiccant module cannot be recharged by heating. Do not attempt to bake the desiccant
module in an oven to remove the moisture as this may result in a fire hazard.
The Internal Desiccant Module (8849) consists of a moisture-absorbent material inside a
poly bag. If the humidity indicator on the front panel turns pink, replace the module and
the back panel perimeter gasket (8606). The desiccant module is located under the CPU
board.
9.13 Memory battery
Random Access Memory (RAM) is a very reliable data storage medium for
microprocessor applications. However, RAM requires power at all times. If power is
removed, the data stored in the RAM chip is lost. Therefore, you cannot power the RAM
chips from the sampler power supply because you would lose data and program settings
every time you unplugged the power cord. A separate battery located inside the sampler
controller is provided to power the RAM chips and the real-time clock. The memory
battery keeps the program entries and logged sample data alive inside the RAM memory
when the main power fails or is removed for transport or replacement.
The sampler memory battery consists of three AA batteries.
Should the memory battery voltage fall too low to properly maintain the program settings,
a warning:
MEMORY POWER LOW
will alert you to replace the batteries. The sampler
utilizes a very small amount of energy from the memory batteries during normal
operation. The service life of the batteries in this application is typically five years.
9.14 Resetting the circuit breaker
Danger
Electrocution hazard. Disconnect AC power from the sampler before attempting to
reset the internal circuit breaker.
Danger
Fire hazard. Continual tripping of the circuit breaker is an indication of a potentially
serious problem with the sampler. Service is required.
The sampler refrigerator has an internal circuit breaker in the Power Junction Assembly
Control Box located in the upper rear compartment (
Figure 40 Power junction assembly
thermal control box on page 114
). If the circuit breaker is tripped, it must be reset.
Important Note: The circuit breaker protects only the heater, compressor, and fan circuits. The
AC-DC internal power supply is protected separately by its own internal fuses.
Prerequisites:
•
Phillips head screwdriver
Important Note: The power junction assembly thermal control box contains electro-static sensitive
components. Avoid contact with all printed circuit board components.
Procedure:
1.
Disconnect AC power from the unit.
2.
Remove the 2 screws from the rear lid.
Goodnal STP ST041 Pre Treatment (Sigma 900 MAX All Weather Refrigerated Sampler) Vendor Manual
Q-Pulse Id VM373
Active 29/10/2013
Page 113 of 122
