IBM System/360 2050 Maintenance Manual page 125

Regulator Vol toge Ripple Test Point
Meter Point.
IA
+6 VAR OIA04G4B09
Gote A-TB-2-4
18 +6 TC OIA04G2004 Gote A-TB-2-5
IC +6 ROS 01CA286B1 I
Gote C-UOB0-12
2 +3 OIAE4M2003 Gote A-TB-2-12
3 +6 OIBB4M2Bl 1 Gate 8-TB-2-12
4 +6
01BA182811
Gote B-T&-1-12
5 +3 01BB4M2003 Gote 8-TB-2-8
6
+3 02BA3M2003
028-TBl-8
7 -3 01AE181806 Gote A-TB-1-10
8
+6 Gate C-UOB0-8
Gate C-UOBD-8
9 +48
Feed Thru Capacitor
Feed Thru Copocitor
C-57 in POU
C-57 in POU
10 -3
02BA3M2B06
Gote 028-TB-1-10
11
+30 01A04G2B02 Gole A-TB-2-1
12
-18 Gate C-UOB0-6
Gote C-UOBD-6
13 +18 M9-8SM 1 TBl-6 M9-BSM 1 TBl-6
14
+56
M9-BSM l TBl-2
M9-8SM l TBl-2
15 +60 M9-BSM 1 TBl -4
M9-BSM l TBl-4
16 +56 M9-BSM 2 TBl-2 M9-BSM 2 TBl-2
17 +60
M9-BSM 2 TBl-4 M9-BSM 2 TBl-4
Reg Reg Meter and Ripple
384K 512K Vol toge Test Point
1 +60
M9-BSM 3 TBl-4
2 +60 M9-8SM 4 TBl-4
2 3 +56 M9-BSM 3 TBl -2
For 384K or 512K Storage
4
+56
M9-BSM 4 TB! -2
3 5 +18 M9-BSM 3 TBl-9
Feature, Located in
4 6 +3
M9-BSM 3 TBl-13
Power Frame 04
5 7 -3 M9-8SM 3 TBl-15
6 8 +6 M9-BSM 3 TBl-11
Note: Maximum allowable ripple is !43 of the nominal voltage. Ripple includes voltage
variation, ripple and noise.
FIGURE 117. VOLTAGE REGULATOR TEST POINTS
Voltage Sequence Problems
To assist in servicing sequence problems, the volt-
age sequencing can be stopped in various points of
its cycle by selectively removing the P2-P6 plugs
from the converter-inverter. For instance, all
power except for the 60 volt XY, the 60 volt Z, and
the -12 ROS voltage can be brought up and examined
if P5 and P6 are removed. An examination of the
YB logic pages shows which regulators are fed from
each plug. This allows you to inspect certain volt-
ages in their proper sequence without possible dam-
age to drivers, etc. , if one of the logic voltages is
not functioning properly.
Plus 18 Volt Sequence Down
The
+
18v should remain up for at least one second
after the loss of the 56XY or 60Z voltages. Adjust-
ing the RC-time constant around the K39 contactor
core (YB221) controls K39 dropout. The following
sequence can be used to adjust the resistor:
124 (3/71) Model 50 FEMM
1. With power down, preset resistor R23 (in
lower right-hand ac compartment) to half its value.
2. With the A probe, monitor the 60Z (regulator
15) at the plus bus.
3. Sync on the fall of 60Z and set the scope
sweep for 1 sec/cm.
4. Set the scope mode switch to see both
A
and
B probes simultaneously (chopped).
5. With the B probe, monitor the output of the
18-volt regulator.
6. Drop power; note the time difference between
the fall of 60Z and 18-volt supplies.
7. Set R23 to approximately one-third resistance
so that the time is at least one second; no harm will
result if the time is more than one second. To
lengthen dropout time, increase the resistance of
R23 (however, if a very high resistance is used, the
dropout time will be greatly reduced instead of
lengthened) .
Once the resistor is set, the difference should be
checked between all 60- and 56-volt supplies (A
probe) and the 18-volt supply; there should be a
delay of at least one second with any one of the 60
or 56 supplies.