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8.1.8 Manual Bring-Up Of The Multilevel,
Dual Level, And Trilevel Supplies
In troubleshooting some power supply problems,
it might be advantageous to bring up the power
supplies manually. In this way the multilevel
supply can be brought up and its voltages checked
before bringing up the dual level or trilevel supply.
However, the following precautions must be ob-
served when manually bringing up the supplies:
CAUTIONS
•
If your problem is overcurrent or overvoltage,
do not use this procedure.
•
If the system has a belt printer, disconnect P6
to prevent possible damage to the hammer
driver cards. For P6 location, see page 4-77.
•
Do not unload the +S.5 Vdc or -5 Vdc singly;
they must be unloaded together to prevent
damage to the FET logic.
• With the power supplies up and the stop lines
(stop multilevel and stop dual level or trilevel)
removed, any error detected will not sequence
down the power supplies.
•
Leave at least one load on each level for volt-
age regulation.
•
Do not use the mainline switch to power down.
•
Always ensure that the dual level supply is
down before bringing the multilevel supply
down.
To manually bring up the supplies, follow this
sequence .. The pins referred to are on the power
sequence card socket.
1.
2.
Turn power off at the operation control
panel. After the power is sequenced down,
turn the mainline switch off.
Remove the power sequence card.
3.
Connect a jumper wire from MOS to P05
(-K1 driver) on the power sequence card
socket.
4.
Turn the mainline switch on. The fans
should start.
5.
6.
To bring up the multilevel supply, touch
a jumper wire momentarily (at least 2
seconds) from POS (ground) to U02 (start
multilevel) on the power sequence card.
Note:
You will hear a hum when the
multilevel supply comes up.
Measure the multilevel voltages.
8-8
Trilevel ....
1--_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
---0.
1 . . . . .
Dual Level
Power Supply
Power Supply
(Serial Printer)
(Belt Printer)
~
~
7.
To bring up the trilevel supply, touch a jump-
7.
To bring up the dual level supply, touch
S.
9.
er wire momentarily (at least 2 seconds)
from POS (ground) to U03 (start dual level
[trilevel] ).
Measure the trilevel voltages.
If a short in the load is suspected, the
trilevel supply is capable of operating with
all load connections removed (that is, E3,
E4, E5).
Note:
The multilevel and dual'level sup-
plies must have the loads connected for
proper operation.
CAUTION
The trilevel supply must be powered down
before the multilevel supply is powered
down.
Connect a meter from E4 (+24 Vdc)
to ground. Power down the trilevel by
connecting a jumper from POS (ground) to
S03 (stop dual level [trilevel1) on the power
sequence card. When the +24 Vdc reaches
o
Vdc, remove the jumper.
S.
9.
a jumper wire momentarily (at least 2
seconds) from POS (ground) to U03 (start
dual level) on the power sequence card socket.
Note:
You will notice a difference in" .
hum.
Measure the dual level voltages.
CAUTION
The dual level supply must be powered
down before the multilevel supply is
powered down.
Power down the dual level by touching a
jumper wire momentarily (at least 2 sec-
onds) from POS (ground) to S03 (stop dual
level) on the power sequence card socket.
10.
Power down the multilevel supply by touching a jumper wire
momentarily (at least 2 seconds) from POS (ground) to S02
(stop multilevel) on the power sequence card socket.
11.
Turn the mainline switch off.
12.
Remove the jumper wire from MOS to P05.
13.
Reinstall the power sequence card in the socket.
14.
If the system has a belt printer, reconnect P6.
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