Service manual

Removal and
Replacement of
Power Supply
1. Disconnect pod cables from rear of instrument.
2. Disconnect power cable.
3. Remove ten screws securing top cover. Remove top cover.
4. Disconnect disk drive cable from disk drive.
5. Remove two screws securing disk drive to power supply. Remove disk drive
by sliding assembly out front panel of instrument.
6. Remove two retaining pins securing power supply to chassis. Slide power
supply out far enough to gain unobstructed access to power supply cables.
7. Disconnect power supply line input and DC output cables. Remove power
supply.
8. Slide new power supply in far enough to connect line input cable and DC
output cable. Connect cables and slide power supply in completely. Secure
power supply using two retaining pins.
9. Slide disk drive through front panel of instrument. Secure disk drive to power
supply using two screws.
10. Connect disk drive cable to disk drive.
11. Install top cover. Secure top cover to chassis using ten screws.
Note To ensure top cover is properly installed, secure side screws of top cover before
securing top screws.
Removal and
Replacement of
Fan
1. Disconnect pod cables from rear of instrument.
2. Disconnect power cable.
3. Remove ten screws securing top cover. Remove top cover.
4. Disconnect fan cable and BNC trigger cables from system board.
5. Disconnect AC power supply cable from power supply.
6. Remove two hex standoffs securing HP-IB cable to rear panel.
7. Remove eight screws securing rear panel. Remove rear panel.
Note An ESD spring ground is inserted on the RS-232 connector. This spring ground is
not secured and can easily fall off.
8. Detach fan from rear panel by removing four screws securing fan to rear panel.
9. Disconnect fan cable from old fan and connect to new fan.
Service HP 1650B/1651B
6-20 Service Manual