OHAUS T71P, Service Manual

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CHAPTER 3 MAINTENANCE PROCEDURES
3.2.2 Display Printed Circuit Board (PCB) Replacement
Repairs are not recommended on the Display PCB. Component parts of the Display PCB are
not stocked by Ohaus. Replacement is recommended rather than repairing.
1. Separate the Top and Bottom Housing. (Follow steps 1 – 3 in Section 3.2.1.)
2. On the T71XW, remove the Main PCB. (Follow steps 4 – 8 in Section 3.2.1.)
3. Remove the four screws holding the Display PCB to the Top Housing.
4. Carefully lift out the Display PCB, to avoid stretching the fine plastic ribbon cable
connected to the Membrane Switch.
5. Gently remove the two ribbon cables – one connected to the Membrane Switch, and
the other to the Main PCB. Avoid bending the pins.
6. Connect the ribbon cables to the replacement Display PCB, and position the board
over the screw holes. Insert the screws and tighten them.
7. Carefully re-position the Main PCB over its screw holes in the Top Cover.
Re-insert and tighten the screws.
8. Reconnect the cables removed in Steps 4 and 5 of Section 3.2.1.
9. On the T71P, re-insert the hex screws connecting the RS232 Interface port to the
Bottom Housing.
10. Close the Housing and re-insert the four screws.
11. Perform calibration procedures. (See Section 1.8.)
12.
Perform testing procedures. (See Chapter 4.)
7000 Series T71 Indicators Service Manual 3-3 Ohaus Corporation www.ohaus.com