Det-Tronics PW9200x Pathwatch IR Gas Detection System - Manual (Page 19)

4. Disconnect the connector plug(s) from the recep-
tacle(s). The transmitter has one connector and
the receiver has two connectors. The instrument
can be inspected or serviced on-site while the
cover is opened and attached by its hinges. If
service is to be performed off-site, the cover and
attached components can be removed from the
housing as described in Step 5.
5. With the cover swung open, lift up to disengage
the hinges. Care must be taken to avoid scratch-
ing the flanges or damaging the internal compo-
nents.
Each time the instrument housing is opened for main-
tenance, the desiccant pack should be checked.
When the desiccant pack is expanded only slightly,
no change is necessary. If the desiccant is expand-
ed to twice or more of its original size, the desiccant
should be replaced. Extra desiccant packets are
available from Detector Electronics (see
“Recommended Spare Parts List.” DO NOT replace
the desiccant until all other maintenance procedures
have been completed. Remove the old desiccant by
cutting the strings that attach it to the power supply
wiring. Remove the plastic bag on the replacement
packet and tie it to the power supply wiring. Be sure
that the desiccant packet is securely attached to the
power supply wiring so that it cannot come loose
inside the housing. Close the cover immediately after
replacing the desiccant.
To reattach the cover to the instrument housing:
1. Holding the cover completely open, slide the
cover pins onto the housing hinges. Do not tight-
en the hinge screws.
2. If necessary, replace the desiccant pack.
3. Reconnect the plug(s) and receptacle(s) in the
housing and close the cover. Guide the cable to
ensure that it is not pinched.
P.C. BOARD AND ASSEMBLY
REPLACEMENT
(See Figure 3 for locations)
SYNCHRONOUS DEMODULATOR AND OPTIONS
P.C. BOARDS
The sync demod board is located to the right and the
options board is located to the left of the filterwheel
motor inside the motorbox. Remove either board by
pulling it out of its connector on the rear panel p.c.
board and sliding it through the card guides out of the
motorbox. To replace the sync demod or options
board, make sure that the notch on the board match-
es the key in the connector and slide the board along
the card guides into the motorbox. Make sure that
the board is seated firmly in the connector.
REAR PANEL P.C. BOARD
The rear panel p.c. board is attached to the side of
the motorbox next to the connector/relay p.c. board.
The sync demod and options boards must be
removed before the rear panel board can be
removed.
To remove:
1. On the connector/relay p.c. board, remove the
STATUS ALARM and HC ALARM relays from their
sockets.
2. Release the ribbon connector that connects the
rear panel board to the connector/relay board.
3. Remove the six sockethead screws that hold the
rear panel board to the motorbox tabs.
4. Pull the top of the rear panel board away from the
motorbox to release the two connectors at the top
of the board.
5. Being careful not to touch the sync pickoff with
the filterwheel, remove the board.
To replace:
1. Being careful not to touch the sync pickoff with
the filterwheel, slide the board into place.
2. Firmly press the connectors at the top of the
board into the mating connectors on the motor-
box.
3. Attach and lock the ribbon connector to the con-
nector/relay p.c. board.
4. Replace the six socket head screws that hold the
rear panel board to the motorbox tabs.
5. Replace the STATUS ALARM and HC ALARM
relays in their sockets on the connector/relay p.c.
board.
AGC/TE COOLER P.C. BOARD
The AGC/TE cooler board is mounted in the detec-
tor/preamp assembly within the fins of the heat sink.
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