Volt Internal Reference Adjustment; Replacement Procedures; Power Supply Replacement - HP 3000 III Series Manual

HP 32421A Series III Power Supplies
b. Adjust the +12ADJ control located on the rear panel of the
power supply for a +12.0 (+/-0.1) V indication on the digital
voltmeter.
9-27. +5.00 VOLT INTERNAL REFERENCE ADJUSTMENT.
internal reference is adjusted as follows:
The +5. OO-vol t
a. Power down the system by placing the corresponding UPPER or
LOWER MEMORY DC POWER switch on the
Dc
Control Panel to
STANDBY and place the corresponding HP 30311A Power Supply
power switch off (down).
b. Remove the power supply from the cabinet and place on a suit-
able s uppor t •
c. Remove the top cover from the power supply.
d. Connect a digital voltmeter between the +5.00 volt internal
reference test point on the control board (figure 9-4) and a
common ground point on the control board.
Note
Allow the digital voltmenter to warm-up for
the recommended warm":'up per iod before ta k-
ing any measurements.
e. Power up the system and allow five minutes for power supply
circuits to stabilize. Measure the +5.00-volt internal ref-
erence voltage (+5.00 +/-O.OOSV).
f. If necessary, adjust R139 on the control board for a +5.00
+/-0.005V indication on the digital voltmeter.
tbte
If an adjustment was necessary, the BATTERY
(FLOAT) VOLTAGE adjustment procedure must
also be performed.
g. Power down the system and disconnect the digital voltmeter.
h. Replace power supply top cover.
i. Install the power supply into the cabinet.
9-28. Replacement Procedures
9-29. POWER SUPPLY REPLACEMENT. The power supply is replaced by
performing the following steps:
a. Power down the system by placing the corresponding UPPER or
LOWER MEMORY DC POWER sw itch on the System DC Control Panel
to STANDBY and place the corresponding HP 30311A Power Supply
power sw itch off (d own) •
9-19