Power Supply Unloading Procedures - IBM 5410 Maintenance Manual

Page of SY31-0244-2
Revised December l, 1971
By TNL: SN31-0307
BSM +3 Volt and -14 Volt Supplies
Determine the CPU storage capacity and storage configura-
tion before checking or adjusting the +3V or the -14V power
supply (Figure 5-2).
The +3 V supply
used by BSM is adjusted by connecting the
meter leads to the test points (Figure 5-2). Then adjust
potentiometer on the upper half of the BSM power supply
card. The + 3V is set by referencing it to the +6V supply
(meter reading will be +3V).
The -14 V supply used by BSM is adjusted by connecting
the meter leads to the test points (Figure 5-2). Then ad-
just the potentiometer on the lower half of the BSM power
supply- card.
See paragraphs 5.5 and 5.6 for the adjustment of the -4V
and +6V supplies. See paragraph 4.2 for the adjustment of
the -30V supply.
5.2.2 Power Supply Unloading Procedures
Figure 5-3 represents each power supply regulator in
System/3. Each terminal shown serves the same function
on all the regulators in the system. The only difference is
the applied input voltage (E 1 to E2) and the resulting out-
put voltages (E3 to E4).
Terminal point E8 receives an error output signal which
causes the system to power down immediately. An over-
BSM Sizes Required
Installed CPU Storage
Capacity and Configuration
SK 12K 16K 24K 32K 48K
64Kl
current, overvoltage, or undervoltage condition generates
the signal. Removal of terminal E8 wires prevents the sys-
tem from detecting a power supply failure. To prevent
possible component damage, avoid removing any wires
from E8.
Terminal point El 2 serves as the start connection to a
regulator. In the unloading procedures that follow the
removal of wires from terminal E 12 prevents start up for a
particular regulator.
0
0
0
/Regulator Heat Sink Assembly
+
E1
I
ES
I
E6
1
1 nput from Logic
and Memory Bulk
t---+-~
Supply
E2
I
E7
I
E8
E3
I
E9 (+bias)
(Error output signal)
I
E10 (-bias)
TB1-1
Black
I
E11
TB1-3
Yellow
I
E 12 (start)
I
E13 (-sense)
I
E14 (+sense) +
1---+----\
Output
E4
Figure 5-3. Power Supply Regulator
Test Points
+3 Volts
-14 Volts
Minus Plus Minus
Plus
8KBSM
x x
01 A-84C4J03 01A-B4C4811 01A-84C4J11 01A-84C4G08
16K BSM
1st BSM
x
x x x
01 A-B4C4J03 01 A-B4C4B11 01 A-B4C4J11 01 A-B4C4G08
and
2nd BSM
x x
and
01 A-A4C4J03 01 A-A4C4J03 01 A-A4C4J11 01A-A4C4G08
or-'
~or
32K BSM
x
x x
2 01 A-B4A4J03 01A-B4A4B11 01A-B4A4J11 01 A-84A4G08
• Figure 5-2. BSM +3V and -14V Storage Capacity and Supply Test Points
5-2