HP 654 A Series Operating Manual page 31

1. Enable the calibration mode by pressing (
Cai Enable
If
Shift
ITYe^^.
2. PASWD will appear on the display.
3. Press the number keys corresponding to the password, followed by
[Enter
). The Cal
annunciator will go on.
Note
On new equipment, the calibration password corresponds to the four- digit
model number (such as (3CD3CD)- Appendix A for more information
about the calibration password.
4. Save any operating state (for example, press
5. Turn the power off and then back on.
A normal display free of error messages should appear. If not, the power supply requires
service.
Runtime Error Messages
Under unusual operating conditions, the VOLT or AMPS display may show +OL or -OL. This
indicates that the output voltage or current is beyond the range of the meter readback circuit.
Table 3-4 shows other error messages that may appear at runtime.
Table 3-4. Runtime Errors
Display
Meaning
EE WRITE ERR
EEPROM status timeout
SBUB FULL
Message too long for buffer
SERIAL DOWS
Failed communication with
front panel
STK OVERFLOW
Front panel stack overflow
UART FRAMING
UART byte framing error
UART OVERRUN
Overfilled UART receive buffer
UART PARITY
UART byte parity error
Checkout Procedures
Turn-On Checkout 3-7