User's Manual

Table Of Contents

EX7100 Technical Manual - Module Descriptions

Test

Number

Fuse

Rating

Positive Probe Negative Probe Expected Voltage

1 TB1 +ve terminal. TB1 -ve terminal. Input voltage ± 0.5V.

2 10 A Fuse F1, both ends. Chassis Ground 22.8 to 25.2V.

3 2 A Fuse F2, both ends. Chassis Ground 14 to 16V.

4 1 A Fuse F3, both ends. Chassis Ground -14 to -16V.

5 5 A Fuse F4, both ends. Chassis Ground 4.8 to 5.2V.

6 250 mA Fuse F5, both ends. Chassis Ground -4.7 to -5.3V.

Table 7.2: Typical Power Supply Test Point Voltages

7.2.3 Alignment

The Power Supply requires no alignment and has no user adjustments.

Two potentiometers are provided: RV301 & RV302. They are factory set to the required

under-voltage and over-voltage shut down thresholds and should not be adjusted

The PSU Measurement board has factory set metering coefficients. These cannot be

adjusted in the field.

7.2.4 Module Replacement Procedure

1. Isolate the EX7100 Terminal from the incoming DC supply by removing the DC input

wires from the rear panel terminal block.

2. Remove the bottom cover as described in Section 6.1.

3. Note the connector positions and the way that the cables are run (it is important that

all cables are replaced as they were initially run before the module replacement

procedure).

4. Disconnect the remote on/off switch loom by unplugging SK301. Remove the wiring

loom plug from PL1 and remove the cable from SK6.

5. Loosen the screws of the terminal block TB1 and remove the DC input wires.

Caution: Remove the six ferrite beads (two per wire) and keep in a safe place for

future replacement.

6. Check, using a multimeter, placed between the earth (on TB1) and the fuse carriers

on the PCB, that the filter capacitors have safely discharged.

7. Remove the nine M3 screws and bushes from the heat-sink mounted

semiconductors. Keep them in a safe place.

8. Remove the six M4 screws and washers holding the PCB and keep them in a safe

place. Carefully lift the PCB out of its housing. Do not carry the PCB by the projecting

semiconductors. The PCB can be safely carried by grasping T1 (the largest

transformer) or by holding it by the edges of the board.