Data General NOVA 4/C Field Engineering Maintenance Manual page 43

Data General Corporation (DGC) has prepared this manual for use by DGC personnel and customers as a guide to the proper installation, operation, and
maintenance of DGC equipment and software. 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.
a. Reposition the plug.
b. Turn the power on.
c. Check the memory disaster light. If it is on, continue
to step 3.
3. Replace the power supply board. If the memory disaster
light is still on, replace the CPU board.
4. If you have already done steps 1 through 3 and the
memory disaster light is still on, replace the internal cable
Over-Current Light
1. Turn the power off.
2. Replace the power supply board.
3. Turn the power on.
4. Check the over-current light. If the light is on, turn the
power off and remove any printed circuit board, other
than the power supply board.
5. Turn the power on.
6. Check the over-current light.
a. If the light is NOT on, replace the board being sure to
insert the correct jumpers (see the appropriate I/O
device documentation).
b. If the light is on, reinsert the removed board, and
repeat steps 4 through 6 with any other printed circuit
board you have not already tried removing.
c. If you have already done steps a and b and the
over-current light is still on, check that the load on the
power supply is balanced (see the Installation Data
Sheets, DGC No. 010-000213, for the load balancing
7. If you have already done steps 1 through 6 and the
over-current light is still on, replace the internal cable
Over-Voltage Light
2. Replace the power supply board.
3. If the light is still on, replace the CPU board.
4. If you have already done steps | through 3 and the over-
voltage light is still on, replace the internal cable (wiring
2. Check the +5V voltage at test plug J1-15 (see Figure
6.8). If +5V is between 5.10V and 5.20V, go to "Final
Checkout"; otherwise, continue the checkout.
/ 1 xm
J35-1 |[goo004o000000eHcooo0o0000o] 335-49
J35-2 (OOD0000000000000050000000} 335-50
DG-06066 J35
Figure 6.7 Jack 35
POWER SUPPLY BOARD
(FRONT VIEW)
J1-8 J1-1
OQO00000
TEST PLUG J1
DG-06067
Figure 6.8 Test plug
4. Short MEMD at J35-21 to GND at J35-1 (see Figure 6.7).
Before continuing the checkout, make sure you have
shorted the correct pins.
5. Turn the power on and check the memory disaster light.
a. If the light is NOT on, turn the power off, remove the
short, and replace the VNR unit.
b. If the light is on, turn the power off, remove the
short, and then turn the power on.
e Check the -11V voltage at J35-25 (see Figure 6.7).
e If -11V is NOT between -11.0V and -12.5V (-30VNR
not ok), check the VREF at test plug J1-14 (see figure
6.8). If VREF is 5.8V, replace the VNR unit; otherwise,
replace the power supply board.
e If -11V is between -11.0V and -12.5V (-30VNR ok),
check the HVS voltage at test plug J1-4 (see Figure
6.8). If HVS is greater then 2.9V, replace the power
supply board; otherwise, replace the VNR unit.
6. Recheck the +5V voltage at test plug J1-15 (see Figure
6.8). If it is between 5.10V and 5.20V, go to "Final
Checkout"; otherwise, try replacing the internal cable
(wiring harness). If this does not work, call DGC Field