HP 654 A Series Operating Manual page 29

Series 654xA and 655xA Supplies

The line fuse is located on the rear panel (1, Figure 2-1). Proceed as follows:

1. Turn off the front panel power switch.

2. Using a screwdriver, remove the fuse from the fuseholder. Replace it with one of the same

type (see Table 1-4 in Chapter 1). Do not use a "slow-blow" type fuse.

3. Turn on the power supply and check the operation.

Series 657xA Supplies

Warning

Hazardous voltage can remain inside the power supply even after it has been

turned off. Fuse replacement should be done only by qualified electronics

personnel.

The line fuse is located inside the power supply. To change it, proceed as follows:

1. Turn off the front panel power switch and unplug the line cord from the power source.

2. Remove the power supply dustcover as follows:

a. Remove the four screws securing the carrying straps and dustcover.

b. Spread the bottom rear of the dustcover and pull it back to disengage it from the front

panel.

c. Slide the dustcover back far enough to expose the line fuse (1, Figure 2-1).

3. Observe the input rail LED under the RFI shield (4, Figure B-3 In Appendix B). If the

LED is on, there is still hazardous voltage inside the supply. Wait until the LED goes out

(this may take several minutes) before proceeding.

4. Connect a dc voltmeter across test points TPl and TP2 (see Figure B-3). It may be

necessary to remove the RFI shield in order to reach these test points. (The shield is

secured by four screws on each side.) When the voltmeter indicates 60 volts or less, it is

safe to work inside the power supply.

5. Replace the fuse with one of the same type (see Table 1-4 in Chapter 1). Do not use a

"slow-blow" type fuse.

6. If you removed it in step b, be sure to replace the RFI shield.

7. Replace the dustcover.

8. Connect the line cord to the power source.

9. Turn on the front panel power switch and check the operation.

Figure 3-1. Series 657xA Line Fuse

Turn-On Checkout 3-5