PCM-2 Manual.pdf - Voss Associates

NOTE:
String the wire such that the completed channel has good wire tension and that
its high voltage jumper wire is beneath the anode wire and is looped nearly
equidistant between the anode wire and the bottom surface of the detector pan.
Manually bend the jumper wire as necessary to achieve this. The anode wire
springs can also be spread apart slightly with a pair of small needle nose pliers to
increase anode wire tension. BE VERY CAREFUL WHEN APPLYING
TENSION TO ANODE WIRE AS IT IS VERY DELICATE AND CAN EASILY
BREAK, Also, inspect the probe's bottom surface at the areas directly below the
wire end for residual flux spots Remove any such residual flux with a clean dry
brush and blow away particles with canned air or dry nitrogen gas.
CAUTION:
DO NOT use compressed shop air as in-line lubricants will contaminate internal
probe chamber surfaces.
13. Apply corona dope to all high voltage connections (i.e. internal exposed banana jack, stainless
steel washer, bare jumper wire and anode wire spring solder joints). Avoid getting corona
dope on the anode wire at any point other than its exit from the solder joint. Apply an
additional dollop of corona dope to each anode wire spring at its outboard bend nearest the
side of the probe chamber. The inboard bend need not be doped (reference drawing).
14. Allow corona dope to dry for approximately 4 hours with the detector pan facing downward
and covered or bagged (to protect it from accumulating airborne dust and contamination).
Following this curing period reinspect the doped anode wire springs and high voltage
connection(s) for any thinly doped areas and touch-up as necessary to completely cover them.
Apply enough corona dope at each wire end to totally enclose the solder joint. Following this
step a minimum 4 hour curing internal must be allowed prior to testing the completed probe.
however, assembly completion may continue.
15. Uncover the detector and silicone face sealing gasket all around its open edge. Unifonnly seat
the gasket down onto the chamber, smoothing out the gasket all around. Verify that the
gasket is properly seated and not kinked in the corners as this may cause serious
detector gas leakage. Avoid stretching the gasket during installation if possible.
16. Clean the exposed top (face) inner and omer flange surfaces of the gasket with isopropyl
alcohol and a clean lint-free wiper to remove any particulates and to provide it some surface
"tack". Be careful not to break the anode, wire(s) with the wiper during this cleaning step.
Then apply a very thin spread of clear vacuum grease (DOW-CORNING High Vacuum
Grease # 976) to the upper face of the gasket all around.
17. Perform a final visual inspection of the probe chamber to check for the presence of any dust
particulate debris. missing corona dope. broken anode wires, etc.
11000-A308/PCM-2 Det. Assy. Procedure/Revision/March 1994 5