HEWLETT PACKARD (HP) HP3457A
Service Manual

Call bra tlon

3457A

5-9. In the event that the security code is unknown, the security feature can be disabled t o permit a new code t o be entered. To disable the security feature, complete the following steps.

a. Remove all power from the 3457A (line cord and external inputs) and turn the unit upside-down. b. Loosen the six captive screws in the bottom cover.
tom cover). ( I t is not necessary to remove these screws from the bot-

c. Return the unit to an upright position and remove the top cover d. Remove the NORM / DSA / KEY jumper (JM532) from the NORM position and place it in the K E Y position. ( J M J 3 2 is located on the A l logic board directly behind the front panel display). e. Reconnect the power and turn the instrument ON. f. Access the SECURE command.

5.

(Press the Blue SHIP?' key then the HECALI, / S configuration key. Use the scroll key t o display the S E C U R E command).

g. Enter the number 0, the delimiter ( , ) and the security number you wish t o use. h. Press the ENT key. i. Disconnect power and return jumper JM532 to the NORM position. j, Replace the top cover, tighten the retaining screws and reconnect the power. The instrument will now respond to the security code just entered.

When jtirnper JM532 is in the KEY position, fhc sccririty feafrrre is disabled. I f is possible to calibrate /he instrrrrnenl wilhorrt enlering a ~ecrrritynumber under f h e ~ e conditions. I f a new stwrrity nrrrnber is nof twtertld whilc fhtl jrrrnper is in the KEY position, the original nrrrnber will again he in e\jec/ whcn jrrrnpcr JM532 is retrrrned to the NORM position.
5-10. Calibration Number (CALNUM?)

5-11. The CALNUM? command provides you with a method of monitoring the number of calibrations performed. By using this command, you can determine whether un-authorized calibrations have occurred. The instrument will always respond the CALNUM query command by displaying the number of calibration RAM entries completed since factory initialization. factory initialization. The maximum calibration number which can be stored is 32767. After reaching the maximum number, the counter resets to 0 and begins again. Please note that the calibration number is increased by one for each calibration point. A complete calibration increases the calibration number by several digits. 5-12. The procedure for reading the Calibration Number is as follows:
a. Access the CALNUM? command.
Use the

5.

(Press the Blue S H I F T key then the OFFSET C O M P / C configuration key. scroll key t o display the CALNUM? command).

b. Press the ENT key.