HP 3000 SERIES II System Service Manual page 166

SYSTEM POWER SUPPLIES
I~
This appendix presents detailed information about system power supply units. Additional
information about power distribution is given in the Engineering Diagrams Manual.
B-1. INTRODUCTION
An HP 3000 Series II Computer System with up to 128K words of memory has three power
supplies:
• HP 30310A Power Supply
• HP 30311A Power Supply
• HP 30312A Power Supply
HP 3000 Series II Computer Systems containing more than 128K words of memory have one
additional HP 30310A and one additional HP 30311A.
The power supplies require preventive maintenance, voltage adjustments, and an occasional
troubleshooting. The following items are required to perform these tasks:
• A vacuum cleaner for removing dust.
• One digital voltmeter with at least a 4-digit readout
and
a minimum input resistance of 10
megohms. The device should have full-scale ranges of 9.999 and 99.99 and accuracy of better
than one percent.
• One oscilloscope.
• One multimeter.
• One autotransformer.
All power supplies are non-repairable items maintained on an exchange basis. Only open fuses
should be replaced in the field.
B-2. HP 30310A POWER SUPPLY
This power supply provides +20, +15, +5, -20, -15, and -5 volt DC outputs. Main assemblies within
the power supply are:
Al
A2
A3
JAN
1977
Preregulator Control PCA
Inverter Driver PCA
20-Volt Supply PCA
B-1
30310-60002
30310-60003
30310-60004