IBM System/360 2050 Maintenance Manual page 99

To check for a missing or extra drive line, use
the ROS addresses in Figure 90. These ROS ad-
dresses all use select line one so each drive line
may be checked at the console until the faulty line
is located. Remember, if two lines are driving at
once, the line that gives no error is the failing line.
To check for a missing or extra select line use
the ROS addresses in Figure 91. These addresses
all use drive line zero so each select line may be
checked at the console until the faulty line is located.
Sense Latch and Strobe
If a strobe is lost, the sense latch will not set and
the corresponding bits will be set into ROSDR.
If a sense latch reset is lost, the sense latch
will not reset and the corresponding bits will not set
into ROSDR.
Figure 92 is a list of test points for the ROS
strobe pulse and the sense latch reset. These test
points can be used to determine which strobe or
reset is failing.
Figure 93 shows ROS sense amplifier and sense
latch card locations.
ROS Cord
Drive
ROS
Addr Location
Line Addr
004 ClD2M6 0 804
006 Cl D2J6 l 806
084 Cl D2F6 2 884
086 C1D2C6 3 886
104 C1D2L6 4 904
106 ClD2H6 5 906
184 Cl D2E6 6
984
186 Cl D2B6 7 986
204 ClC2M6 8 A04
206
c
1C2J6 9 A06
284 C 1C2F6 10 A84
286 ClC2C6 11 A86
304
ClC2L6
12 804
306 ClC2H6 13
806
384
C 1C2E6 14 884
386 C 1C2B6 15 886
404 Cl82M6 16
(04
406 Cl 82J6 17
(06
484 C 1 82F6 18 C84
486 Cl 82C6 19 C86
504 C 1 82L6 20 D04
506 Cl 82H6 21 D06
584 Cl 82E6 22 084
586 Cl 8286 23 086
604 ClA2M6 24 E04
606 C1A2J6
25 E06
684
ClA2F6 26 E84
686 ClA2C6 27 E86
704 C1A2L6 28 F04
706 ClA2H6 29 F06
784 ClA2E6
30 F84
786 Cl A2B6 31 F86
ROS Ripple Test
The ROS ripple test tape can be generated with diag-
nostic program 5350. For systems using disks only,
use program 5FE5 to generate a ROS ripple pack.
Since the ROS ripple test checks only the parity of
the ROS words, no test tape update is necessarywhen
EC activity affects the ROS bit planes.
The first record on the ROS ripple test tape pack
checks all planes. If it is desired to ripple only one
given plane, depress system reset pushbutton, and
FLT load the next record. The second record rip-
ples plane zero; the third record ripples plane one;
etc.
Basic ROS Ripple
1.
Set the check control switch to stop position.
2. Place the ROS ripple test tape or pack on an
available unit; set the address of the unit in the
load unit switches; press the load pushbutton.
3. The first section loads and ripples all planes.
If an error occurs, the program stops and the hard
Card Drive
Location
Line
DlA2L6 32
D1A2H6 33
DlA2E6
34
DlA286 35
DlA2M6 36
DlA2J6 37
DlA2F6 38
D1A2C6 39
D l B2L6 40
D182H6 41
0182E6
42
Dl B2B6
43
Dl82M6 44
Dl82J6 45
Dl B2F6 46
Dl82C6 47
DlC2L6 48
DlC2H6 49
DlC2E6 50
DlC286 51
D1C2M6 52
DlC2J6 53
DlC2F6
54
D1C2C6 55
D1D2L6 56
01D2H6 57
Dl02E6 58
Dl0286 59
01D2M6 60
Dl02J6 61
D1D2F6 62
01D2C6 63
Note: All of the cords indicated above use output pin 813 for scoping. When o line is addressed,
it should pulse. If not conducting, the line should
be
at +2v. If this level is down only 3/4(0.75)v,
trouble is indicated.
FIGURE 90. ROS DRIVE LINE TESTS
98 (3/71) Model 50 FEMM