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Single Pulse Operation
The computer can be placed in the single pulse mode by connecting a jumper from
ground to AlE34-15 (see LBD No. O. 135 in Volume III).
With the jumper thus installed
a single timing level is executed each time the START button is depressed.
In the single pulse mode, memory cannot be accessed.
Any attempt to enter into
registers will cause erroneous operation.
MEMORY MAINTENANCE PROCEDURES
General and detailed maintenance data and procedures are given in the following
paragraphs to assist maintenance personnel in the troubleshooting and maintenance of the
computer memory.
Visual Inspection
Conduct a visual inspection periodically.
Watch for accumulation of dust, dirt,
improperly seated PACs, and damaged or improperly dressed cable and signal leads.
Check that all connectors are securely mated and that the cooling fans are operating prop-
erly.
Clean fan filters periodically.
Preventive Maintenance Procedures
The memory is thoroughly tested prior to installation in the computer.
All planes
are tested simultaneously under all ZEROs, all ONEs, and worst-pattern conditions.
The
drive voltage and strobe timing are set so that optimum operating margins result.
The
memory should be tested periodically, as a preventive maintenance procedure, by using a
memory test program.
Drive Voltage Calibration Procedure. -- The drive line currents are determined by the
setting of the 24-vdc supply and the precision resistors which are mounted on the resistor
plates.
The 24v supply RP-61 is temperature compensated by a thermistor which is
mounted near the core stack.
The 24v supply calibration should be periodically checked
according to the following procedure.
a.
Turn off the ac power to the RP-61 Power Supply.
Disconnect the thermistor
by removing the leads going to the power supply Rt terminals.
Connect a fixed 4. 7K±lo/o,
l/2w resistor to the Rt terminals of the RP-61 using a T and B RB-250 terminal attached
to each lead of the resistor.
b.
Turn on the ac power to the RP-61.
Use a voltmeter with at least ±3% accu-
racy to set the 24v supply to the average of the values shown on the core stack nameplates.
The nameplate value is the optimum voltage setting of the power supply at 25 °C.
A
4. 7K resistor instead of a thermistor was used to eliminate calibration temperature depen-
dence.
The voltage was determined prior to shipment, as follows: setting the RP-61 to the
voltage which gives the best operating margins; replacing the thermistor with a 4. 7K resistor;
and, recording the resultant voltage.
3-4
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