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a.
Insertion of the Pre-Patch Panel
Before inserting the pre-patch panel, the operator should verify that the patch blocks
on the pre-patch panel are aligned in the same order as the computing components.
Hold the pre-patch panel at a slight angle and place it in the patch bay groove;
see Figure 2.
Move the pre-patch panel to
th~
right until it contacts the right-
hand side of the patch bay.
Gently, push the pre-patch panel forward until it is
flush with the computer.
Turn the locking lever down; the pre-patch panel will
slide to the left.
To remove the pre-patch panel, apply a light pressure to the panel to keep it from
falling forward when dis-engaged, and lift the locking lever.
b.
Feedback for the Amplifiers
All operational amplifiers should be provided with feedback whenever the computer
is turned on.
Bottle plugs, connected as shown in Figure 3a, provide feedback and
prepare the amplifiers for use as standard inverters or summers.
c.
Application of Power
Connect the computer line cord to a receptacle following the precautions given in
the
TR-20
Maintenance Manual, and place the OFF-ON switch to the ON position.
Place
the RESET-HOLD-OPER switch to the RESET
~osition.
Initially, the amplifier over-
load alarm system will be triggered due to transients; after a few seconds, the over-
load indication should cease.
d.
Amplifier Balance
Under normal circumstances, the amplifiers will remain balanced for periods of weeks.
However, at intervals it is desirable to check this condition.
If an amplifier is
found to be unbalanced, an adjustment should be made.
If the check indicates that
the amplifier balance is rithin tolerance, no adjustment is necessary.
The amplifier must have some sort of feedback in order to be balanced.
Normally,
this requirement is satisfied by the circuit in which the amplifier is used.
The
amplifier may be balanced while normal inputs are applied.
Each amplifier has a
balance potentiometer located behind a hinged cover plate below the Control Panel
(Figure 4).
The balance controls are labeled with the number of the amplifier they
serve.
To set a balance control, proceed as follows:
(1)
Place the computer in the reset mode.
Place the VoltmetEr Function
switch in the BAL position.
Rotate the AMPL SEL switch to the number of the ampli-
fier to be balanced.
(2)
Vary the appropriate Amplifier Balance control until the Vokmeter
reads within two or three divisions of zero.
(The amplifier overload alarm system
may be triggered during the balancing process.)
8
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