HEWLETT PACKARD (HP) 412A
Manual de Servicio

Model 412A

Sect.1 Page 1

SECTION I GENERAL DESCRIPTION
1-1 GENERAL

The Model 412A DC . x u u m Tube Voltmeter is a precision, wide range, multipurpose instrument which covers the entire range of voltage, cufrent, and resistance measurements normally encountered in electronic equipment. It measures voltages from less than 0.1 millivolt to 1000 volts, currents from less than 0.1 microampere to l a m pere, and resistances from 0.02 ohm to 5000 megohms.
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D A M A G E IN S H I P M E N T

male connector recommended by the National Electrical Manufacturers� Association. The third contact is an offset round pin added toa standard twoblade connector. This contact grounds the instrument when used with an appropriate receptacle. An adapter should be used to connect the NEMA a standard two-contact output. When the plug to adapter is used, the ground connection becomes a short lead from the adapter. This lead should be connected to a suitable ground for the protection of operating personnel.

Inspect and operate this instrument upon receipt. Section IV includes a performance check which is a good test as part of incoming quality control inspection. The check can be made with the instrument in its cabinet. If there is any damage, see the �Claim for Damage in Shipment� paragraph at the r e a r of this manual.
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P O W E R CABLE

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230 V O L T O P E R A T I O N

The 412A is normally wiredat thefactoryfor operation from a 115 volt, 50-60 cps power source. To convert it for use from a 230 volt, 50-60 cps power source, change the dual 115 volt primary windings of the power transformer from a parallel combination to a series combination. See schematic diagram for details. At the time of conversion, change l i n e f u s e from 1/2 ampere, slowblow type to 1/4 ampere, slow-blow type.

The three-conductor power cable supplied with this instrument terminates in a polarized three-prong