MKS 651C - Chapter Seven: Battery-Backed Memory Module; Replacing the Battery-Backed Memory Module; Opening the Unit

Chapter Seven: Battery-Backed Memory Module Re
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Chapter Seven: Battery-Backed Memory Module
Replacing the Battery-Backed Memory Module
The 651 pressure controller has a battery-backed memory module which stores configuration and
learned
system information while power is off. The battery-backed memory module (MKS part
no. 037-9227) is specified to provide at least seven years of memory storage under all operating
conditions. No maintenance should normally be required during this period.
Note
The module is also available from the following sources:
•
Bench Marq (BQ 4011MA-100)
•
SGS-Thompson (MK 48Z32B-10)
•
Dallas Semiconductor (DS 1230AB-100)
Eventually, the memory module will need to be replaced. If the 651 unit continually requires
relearning at each power cycle (power off then on again), it may be time to replace it. The
memory module is located on the CPU board inside the electronics unit and may be replaced by
MKS or other qualified personnel.
Opening the Unit
Warning
The 651 unit has lethal voltages inside. Servicing of the unit
must be performed by qualified personnel only.
To avoid an electrical shock, disconnect the power line
before
opening the unit.
1. Turn the power off.
2. Disconnect the AC power cord.
Caution
To avoid damage to sensitive internal components, personnel should
be grounded through a safety impedance while working inside the
651 unit, and the unit itself must be static-free.
3. Remove the two Phillips screws located at the top of the rear panel.
4. Disengage the cover from the rear chassis by lifting it up from the clips.
5. Remove the top cover by firmly pulling it up and back to clear the top of the connector
plates.