Panametrics PanaFlow MV80, User Manual, Page: 153 / 184

PanaFlow™ MV80, MV82 & MV84 User’s Manual 141
Chapter 5. Troubleshooting and Repair
5.6 Electronics Assembly Replacement (All Meters)
CAUTION!
The electronics boards are electrostatically sensitive. Wear a grounding wrist strap and
make sure to observe proper handling precautions required for static-sensitive
components.
WARNING!
Before attempting any flow meter repair, verify that the line is not pressurized. Always
remove the main power before disassembling any part of the mass flow meter.
1. Turn off the power to the unit.
2. Locate and loosen the small set screw which locks the larger enclosure cover in place. Unscrew the cover to
expose the electronics stack.
3. Locate the sensor harnesses which come up from the neck of the flow meter and attaches to the circuit boards.
Make note of the location of each sensor connection (see Figure 121 on page 137 or Figure 122 on page 137). The
vortex sensor connection is on the left, the temperature sensor connection (if present) is second from the left,
and the pressure sensor connection (if present) is on the right. Use small pliers to pull the sensor wiring
connectors off of the circuit boards.
4. Locate and loosen the small set screw which locks the smaller enclosure cover in place. Unscrew the cover to
expose the field wiring strip. Tag and remove the field wires.
5. Remove the screws that hold the black wiring label in place and remove the label.
6. Locate the 4 Phillips head screws which are spaced at 90-degrees around the terminal board. These screws hold
the electronics stack in the enclosure. Loosen these screws (Note that these are captive screws and they will stay
inside the enclosure).
7. Carefully remove the electronics stack from the opposite side of the enclosure. If the electronics stack will not
come out, gently tap the terminal strip with the screw driver handle. This will loosen the rubber sealing gasket on
the other side of the enclosure wall. Be careful that the stack does not become tangled on the loose sensor
harnesses.
8. Repeat steps 1 through 6 in reverse order to install the new electronics stack.