IBM System/360 2050 - Page 89

~ t\
l-
.~
TI ~
r.-
ulL
,..
V\:,
Q
FIGURE 72. INHIBIT PULSE WITH GROUNDED SENSE
INHIBIT LINE OR SHORTED INHIBIT DRIVER
The placement of the strobe turn-on is a control-
ling factor in the operation of the M9/M9A. To get
the strobes in the approximate area of best operation
look at the output of the sense amplifier card and
set the strobes so that there is a small porch on the
leading edge of the pulse (Figure 73). See AAOOO for
strobe timings of the M9 and M9A.
..A
!:...
Porch~
1
\
1-
rr.
,(.,.
.1'<.11
......
vv
"'II
w r""-
, ....
1·r1
FIGURE 73. OUTPUT OF GOOD SENSE AMPLIFIER (M9 ONLY)
Storage Waveforms (Voltage Probe)
Figures 74-76 are waveforms for storage select,
terminator gate, and X and Y gate decode and X
write/read drivers. The sync point for these figures
is plus read A1H6Gl2 (MAOll). Figures 74-75 were
taken while rippling storage from the storage test
switch. Figure 76 was taken while continuously
addressing one location. Because of phase reversal,
the figures of Y drive lines have a double trace. A
good scoping procedure is to scope the yellow wire
on the X and Y read and write terminators (Figure
75). Scoping this point detects open, shorted, or
weak drivers (see Figure 77).
88 (3/71) Model 50 FEMM
rv
~
I ..l
~ I
IA. J.....
_....
Storage Select
Al H6G05 (MAOll)
0. 2 us/cm; 1 v/cm
FIGURE 74. MAIN STORAGE SELECT-WAVEFORM
.~
00.
.........
rv
·-
~
]
v.v.
:\
i...
fl
fl
IVI\
1
l.~
I.\
1
.. ,
I
y
JJ. I\
1
\
-
~
X-Read Terminator Gate
81M2G02 (yellow wire) M8091
0. 2 us/cm; 20v/cm
X-Wri te T er mi no tor Gate
81M2J02 (yellow wire) MB091
0.2 us/cm; 20v/cm
Y-Read Terminator Gate
BIM2D13 (yellow wire) MB091
0. 2 us/cm; 20v/cm
Y-Write Terminator Gate
81M2B13 (yellow wire) MB091
0. 2 us/cm; 20v/cm
FIGURE 75. MAIN STORAGE TERMINATOR-WAVE FORMS
Sense Amplifier Output (M9)
If no porch is on the leading edge of the pulse
(Figure 73), the strobe turn-on is too late and should
be moved ear lier. If the porch on the leading edge
of the pulse is too long (over 60 ns), the strobe turn-
on is too early. Setting the strobes using the porch