CHAPTER 3 MAINTENANCE PROCEDURES
3.2.1 Main Printed Circuit Board (PCB) Replacement
Repairs are not recommended on the Main PCB. Component parts of the Main PCB are not
stocked by Ohaus. Replacement is recommended rather than repairing.
1. Unplug the Indicator from the AC Adapter.
2. Remove the four screws from the Bottom Housing.
3. Carefully separate the Top Housing and Bottom Housing – on the T51P, disconnect
the Display PCB’s ribbon cable from the top of the Main PCB.
4. Pull all cable connectors from their plugs on the Main PCB, including (on the
T51XW), the Display PCB’s ribbon cable from the Main PCB.
5. If cable-leads are connected to Alternate Load Cell Connector J4 (see Figure 1-3),
loosen terminal block’s set-screws and remove the leads.
6. On the T51P, remove the hex screws connecting the RS232 Interface port to the
Bottom Housing, so the port will clear when the PCB is lifted out.
7. Remove the four screws from the PCB. (…and, on the T51XW, a fifth securing the
grounding cable to the PCB on the lower left.)
CAUTION
When handling the PCB, grasp it by the edges only! Always use an anti-static kit!
Do not touch the foil side. Static discharge may damage some components.
8. Lift out the PCB.
9. Carefully re-position the replacement PCB over the screw holes in the Top Cover.
Re-insert and tighten the screws.
10. Reconnect the cables removed in Steps 4 and 5.
11. On the T51P, re-insert the hex screws connecting the RS232 Interface port to the
Bottom Housing.
12. Close the Housing and re-insert the four screws.
13. Perform calibration procedures. (See Section 1.9.)
14.
Perform testing procedures. (See Chapter 4.)
Ohaus Corporation www.ohaus.com
3-2
5000 Series T51 Indicators Service Manual
Summary of Contents for T51P
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