Replacing The Epc Modules - Agilent Technologies 7820A Service Manual

Replacing the EPC modules

128
Agilent 7820 GC Service
1 Access the EPC module. See Accessing EPC modules (
127).
Hazardous voltages are present in the
mainframe when the GC power cord is connected.
Avoid a potentially dangerous shock hazard by
disconnecting the power cord before removing
any GC panels.
Components can be damaged by static electricity:
be sure to wear an ESD strap grounded to the GC
chassis while performing this procedure.
EPC modules are secured by one clamp on the top edge.
Remove the retaining clamps holding the EPC module in place.
Remove the 1/8 inch Swagelok gas supply tubing connections
(1, 2, or 3) from the EPC module.
Lift the EPC module up and remove the communication buss
connector. The SSL EPC modules also require removal of an
electrical connector to the split vent valve.
Remove the tubing blocks (for an inlet or PCM) or manifold
connections (for the detector universal EPC).
Remove the EPC module by lifting straight up.
Install the new EPC module. Remember to plug in the
Communication buss. If a SSL also plug in the split vent valve.
Remove the O-rings for the pneumatic tubing blocks (as
applicable). Clean the sealing surface under the O-rings with a
lint-free cloth. Install new O-rings.
Install the new pneumatic tubing blocks or manifold connections
and tighten.
Turn ON the GC and configure the EPC module.
Zero the flow and/or pressure sensors (Options / Calibrations).
Verify the flow or pressure control.