Data General NOVA 4/S Manual page 46

maintenance of DGC equipment and soft ware. The drawings and specifications contained herein are the property of DGC and shall neither be reproduced in whole or
in part without DGC's prior written approval nor be implied to grant any license to make, use, or sell equipment manufactured in accordance herewith.
Battery Backup Checkout
Only carry out this checkout if the system has battery
backup. This procedure will not discharge the battery a
significant amount. Note that it takes 16 hours for the
battery to fully recharge.
Turn the power on and unplug the chassis ac line
cord from the cabinet.
Check the +12 MEM voltage at location J35-3 (see
Figure 6.7).
a. If this voltage is GREATER THAN 11.0 volts and
remains CONSTANT for MORE THAN 1 MINUTE,
continue to step 3 of this checkout; otherwise,
b. Check the BAT+ voltage at jack J3-1 (see Figure
6.9).
e If BAT+ is greater than 12V, replace the
power supply board.
measure the voltage DIFFERENCE between
J3-5 and J3-6 (see Figure 6.9). If it is greater
than one volt, replace the battery; otherwise,
replace the VNR unit.
VNR UNIT
J3-1
Figure 6.9 JACK3
3. Check the battery backup light on the front console,
a. If this light is on, plug the power cord into the ac
source and then go to Chapter 5, "Computer
Self-Test."
b. If the hght is NOT on. replace the power supply
board, and if the light still does not turn on,
replace the console PCB assembly.
. Plug the ac line cord back into the cabinet.
WARNING: The power supply board generates dangerously
high voltages. DO NOT ATTEMPT TO MEASURE VOLTAGES
INSIDE. Before you remove the cover on the power supply board
WAIT AT LEAST 5 MINUTES AFTER POWERING DOWN THE
SYSTEM to allow the high voltages to dissipate.
Complete all steps in the order in which they are
presented. (Step 3 is only for systems with battery
backup.) Failure to do so may result in a longer system
down time and unnecessary assistance from DGC Field
Service.
indicated that unit was faulty. If the check. still
before continuing. Procedures for replacing field
replaceable units are given in Chapter 14.
IMPORTANT: The steps for troubleshooting the power
supply assume the following conditions:
e The CPU board is in the chassis. (An unloaded
power supply will not produce regulated outputs
so do not troubleshoot the system without at least
the CPU board in the chassis.)
e All the electrical conections between units are
If you have any reason to think that these conditions