OHAUS T71P, Service Manual

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CHAPTER 1
GETTING STARTED
7000 Series T71 Indicator Service Manual 1-5 Ohaus Corporation www.ohaus.com
1.6 HARDWARE SETUP OR DISASSEMBLY
Both the T71P and T71XW connect to a scale base through a Load Cell Cable that connects to
the Indicator’s Main Printed Circuit Board (PCB).
CAUTION :
ELECTRICAL SHOCK HAZARD. REMOVE ALL POWER CONNECTIONS TO THE
INDICATOR BEFORE SERVICING OR MAKING INTERNAL CONNECTIONS.
The process of opening the Housing varies slightly for each model:
T71P:
1. Remove the four Phillips head screws
from the rear housing.
2. Open the housing; disconnect the
ribbon cable from the top of the PCB.
T71XW:
1. Remove the four hex head screws from
the rear housing.
2. Open the housing by carefully pulling
the top of the front housing forward.
Figure 1-2 shows T71’s Main PCB, with connectors, jumpers, terminals and switches indicated.
Figure 1-3. Printed Circuit Board (PCB), T71 Indicator.
1.6.1 Connecting the Scale Base’s Load Cell
The T71P has a circular connector jack on its Bottom Housing. The white plastic six-wire plug
connects to the Scale 1 Load Cell Connector J14. (See Figure 1-3.)
Attach a base without a circular connector to one of the Load Cell Terminal Blocks on the Main
PCB. Pass the load cell cable through a Cable Gland (see Figure 1-1) and attach it to Terminal
Block J4 or Terminal Block J7. (See Figure 1-4.) Tighten the Cable Gland to secure the cable
and maintain a tight seal. Jumper connections must be shorted or opened as follows:
Figure 1-4. Load Cell Terminal Blocks J4 (Scale 1) and J7 (Scale 2).
Power Supply
connector
Battery
connector
(T71P only)
Scale 1 Load Cell
Connector J14
(T71P only)
Real Time
Clock Battery
Scale 2 Load
Cell Terminal
Block J7
Scale 2 Sense
Jumper W4
RS232 Terminal J7
(T71XW only)
External Input
Terminal Block J9
COM2 Connector
J8 (Optional:
RS232 or
RS422/485)
RS232 Connector
(T71P only)
Scale 2 Sense
Jumper W3
Scale 1 Sense
Jumper W2
Scale 1 Sense
Jumper W1
Scale 1 Load Cell
Terminal Block J4
Alibi Option
PCB Connection
Rechargeable
Battery
Connection J3
(T71P opposite side)
Security Switch
SW1