OHAUS T71P, Service Manual

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CHAPTER 2 TROUBLESHOOTING
2.1 INTRODUCTION
This section of the manual covers visual inspection of the Indicator, troubleshooting, and a
Diagnostic Guide, Table 2-1. For setup and connection to either a known good base or
simulator, see Chapter 1. Follow all directions step by step. Make certain that the work area is
clean and use care when handling components of the Indicator.
2.2 VISUAL INSPECTION
Carefully remove the Indicator from its packing container and remove any packing material
fastened to the unit. Note all items supplied with the unit such as AC power supply, cables,
instruction manual, weights, etc. Keep a record of all items and note their condition.
1.
Examine the Indicator for signs of abuse such as a cracked top cover or base, damage
from liquids, cracks on corners, which may suggest the unit was dropped.
2. Open the Indicator by removing the four screws in the rear housing. Be careful not to
stretch the cables that connect the main Printed Circuit Board (PCB) to the outlets
(RS232 and Load Cell ports) and power supply.
3. Examine the top of the main PCB for cracks or signs of corrosion.
4. If it appears that corrosion may have affected the board and you want to examine the
bottom of the PCB, remove the four screws holding it to the housing.
5. Carefully lift out the main PC board. If it is cracked or shows signs of corrosion, it
requires replacement. See Chapter 3, Maintenance Procedures, for board replacement
and testing. If the Indicator shows no sign of physical damage, continue with procedures.
See chart below for visual checking procedures.
Figure 2-1. Visual Checking Procedures.
7000 Series T71 Indicators Service Manual 2-1 Ohaus Corporation www.ohaus.com