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4.2 XVZ DRIVE VOLTAGE (-30V) REOPTIMIZATION
(ALL SYSTEMS)
Reverify drive voltage marginal limits whenever replacing
S/Z, timing, driver source, or strobe driver cards.
To reoptimize the drive voltage:
2.
Loop storage diagnostics
#
97. (Use the proper switch
settings for the storage size of the system.)
Determine the lower drive voltage (-30V) limit by
slowly decreasing the drive voltage reading until an
error occurs. Record the last operating voltage as the
lower limit. If system reset and start does not start
the diagnostic, set the drive voltage close to normal
and reload the diagnostic. Determine the upper limit
by slowly increasing the voltage reading until an error
occurs (do not exceed a more negative voltage than
-3SV). Record the last operating voltage (or -35V)
at the upper limit.
Note: The BSM should run error free for a minimum
of 30 seconds at the last operating point.
3.
Set the XYZ drive voltage {-30 volts) to the optimum
drive voltage which is the average of the upper and the
lower BSM limits.
4.
If the difference between the upper and lower limits
is less than 2.4V, strobe reoptimization may be
necessary.
Note: When reoptimizing the drive voltage or strobe
setting, a thermometer (part 5392366 or any standard
thermometer) placed at the base of the array should
read between 68 degrees and 86 degrees F. The vol-
tage may be reoptirnized outside of this range, but a
check at the normal temperature should be made as
soon as possible.
Page of SY31-0244-2
Revised December 1, 1971
By
TNL: SN31-0307
1
4.3 ST. ROBE SETTING REOPTIMIZATION (8K-16K-32K
SINGLE BSM)
To reoptimize the strobe setting:
2.
3.
4.
Loop storage diagnostics 'lf97. (Use the proper switch
settings for the storage size of the system.)
Refer to the decal on the XYZ current limiting
resistor cover (Figures 4-l, 4-2, 4-2B). Use the
present strobe setting, and determine the upper and
lower XYZ drive voltage limit, which is explained by
4.2, step 2. Record these limits as Figure 4-6 point A
and B show. Repeat 4.2 step 2 for strobe setting 10,
20, and 30 nanoseconds before and after the present
strobe setting. Strobe settings are made on the strobe
driver earn (SR254 ).
Note: These test settings may be wirewrapped on the
strobe card but the final setting must be made with
the jumpers (part 5159491) because the card pins
are not 'squared off as they must be for reliable
wirewrap connections.
Plot the XYZ drive voltage limits as Figure
4-
7 shows.
Set final strobe timing midway between points where
the XYZ driver voltage limits start to drop off.
Set the optimum drive voltage {-30V) which is the
average of the upper and lower BSM limits at the
selected strobe setting (Figure 4-6).
BSt~j
access time is measured when Rd Call/Write Call
becomes active
in the BSM until all sense data latches
are active. (Measure access time while writing all ones
into the BSM.) Access time must be 445 nanoseconds
or less. If necessary, reset the strobe setting to obtain
445 nanoseconds or less. The minimum 2.4V spread
for XYZ voltage must still be met at the new setting.
Note: If the strobe driver card is replaced, strobe
jumpers must be put in the new strobe driver card.
5410
MM
4-9
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