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Chapter 4. Checks, Adjustments, and Removals
Section 1. Basic Unit
4. 1 CPU TI MI NG
Timing for the CPU is developed from a
cryst.3.l controlled oscillator.
The CPU
clock is located in board position B2-C4
and D4 on the A-gate.
4.1.1 SPECIFICATIONS
1.
Oscillator frequency:
5. 56 MHz ± • 033.
2.
T-Puls es (Figure 4-1 and 4-2):
a.
Width--180 ns +25/-10 ns, measured
from the 1 .. 2V level of the leading
or rising edge to the 1.9V level of
the trailing, or falling edge.
b.
Level--each pulse has a down level
of 0.49V to 1.06V, and an up level
of 2.68V to 3.33V.
c.
Overlap--adjacent T-pulses are
overlapped by 90 ns +25/-10 ns as
measured from the 1.2V level of the
rising pulse to the 1.9V level of
the falling pulse.
d.
Skew--the skew between TO pulse and
T2 pulse (and subsequent alternate
pulses) on the transmission line is
+30/-25 ns, as measured from the
1.
9V level of the falling pulse to
the 1.2V level of the rising pulse.
3.
Clock Pulses On the Boards:
(applies
t::>
nets driven by line receiver-power
driver):
a.
T-pulses--(180 ns) have +20/-40 ns
tolerance as measured from the 0.3
volt level of the rising pulse to
the 1.8 volt level of the falling
pulse.
b.
P-pulses--(90 ns) have +20/40 ns
control tolerance as measured from
the 0 .• 3 volt level Of the rising
pulse to the 1. 8 volt level of the
falling pulse.
4.2 CORE STORAGE
ARR~Y
TEMPERATURE CONTROL
4.2.1 COOLING
The BSM (Basic Storage Module) provides the
SLT cards with forced air cooling with fans
operating at 208-volts ac 60-cycle single
phase, or 220-vol ts ac 50-cycle single
phase.
4.2.1.1 Specification
The maximum temperature anywhere within the
BSM must not exceed 133FC55C).
4.2.2 HEATING
A heater, fan, and associated control
circuitry provide a wide temperature range
by maintaining the core array at a fixed
elevated temperature.
The heater element,
control circuits, temperature adjustment,
and temperature sensing devices are
packaged in a complete heater subassembly
that is part of the BSM.
1.
The array inlet temperature must be
maintained at 105±3F(40.4±1.7C).
2.
The low temperature light on the
console must go off when the array
inlet temperature exceeds
96±5F(35.6±2.8C).
3.
The thermal trip mechanism (normally
closed switches) operates at over and
under temperatures of 120±3F and
96±5F(49±1.7C and 35.6±2.8C).
4.2.2.2 Heater Adjustment
Do not attempt to adjust the array inlet
temperature if the machine ambient
temperature is greater than 95F(35C).
1.
With power on, allow five minutes for
warm-up.
2.
Carefully insert a nonmetallic
thermometer (part 5392366 or equivalent)
through the array cover access hole and
into the rear of the heater plenum.
The thermometer should extend about
3.25 in.
(82,6 mm) into the unit and
the tip should be slightly downward.
3.
The heater adjustment potentiometer is
adjusted from the front of the heater
box.
Turn the potentiometer clockwise
to decrease the temperature or
counterclockwise to increase the
temperature until a stabilized
temperature of 105 ±3F(40. 4±1. 7C) is
indicated.
Allow about three minutes
for the thermometer to record properly.
4.
Remove thermometer.
2025 FEMM (7/69)
4-1
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