Table of Contents
Advertisement
1-4
advertant1y patched to ground or to each other.
(Dangling patch cords rarely
short to ground because of the plastic patching blocks and because the metal
strips between the patching block are covered with a scratch-resistant, non-
conductive paint.)
1.2.2
Preliminary Operating Considerations
The following steps are recommended prior to operating the 580 to prevent
possible false trouble indications.
1.
Be sure that all operational amplifiers have four-pin bottle
plugs properly placed and seated as shown in Figure 1.4.
This provides the amplifier with feedback.
The procedure for
inserting and removing the pre-patch panel is described in
Paragraph 1.2.3.
2.
Turn. the computer on and depress the SP (set pot) button.
Initially, the overload lamps of the operational amplifiers
will light due to transients; after a few seconds, all of
the lamps should extinguish.
3.
Check the various supply voltages of the 580.
All power supply
outputs are connected directly to the voltmeter FUNCTION switch
(through appropriate scaling resistors); thus, the check may
be accomplished simply and rapidly.
(See Paragraph
1.3.5
of
this section.)
4.
Allow a few minutes warm-up (at least 1/2 hour for the
DVM)
time to assure that the computing components (including the
DVM)
are up to normal operating temperature.
Ground the
input,termination in
"pp"
address mode designated
DVM
on the
control tray and adjust the
DVM
zero control (Figure
1.5)
for
a +0.000 reading.
Should the polarity relay begin to chatter,
turn the zero control slightly clockwise until the chatter
stops and the indicators retain the +0.000 display.
The
DVM
zero adjustment should be checked daily.
Initially, this ad-
justment may be required more frequently due to aging of the
components.
5.
Closed relay contacts provide a lOOn feedback resistor for
the operational amplifiers when in the set pot mode of the com-
puter (SP button on the control panel depressed).
(This
feature permits pre-patch panel removal without overloading
the amplifiers.)
However, when the computer is switched from
set pot to another mode, the relay contacts open and the ampli-
fier feedback loop is determined by the patching on the pre-
patch panel.
The amplifier overload indicators may be trig-
gered momentarily during the switching time.
This is of no
consequence since the computer should always be placed in the
initial condition mode before going to the operate mode.
Advertisement
Table of Contents
