IBM 7090 User Manual

Service Checks
If the motor will not operate, check the plug connection and also check for a blown
fuse. The fuse is located under the right-hand motor mounting bracket.
Adjustment
A slight adjustment of the relative' position of the motors can be made by loosening
the mounting screws, moving the motor, and retightening the screws.
Removal and Replacement
The right-hand motor may be removed by taking out the mounting screws and mounting
bracket, and then slipping the shaft out of the rubber coupling sleeve after the set screw
is loosened.
Removing and replaCing the left-hand motor is somewhat more involved. There is
little or no room to move the motor to the left, out of the coupling sleeve; therefore,
the coupling sleeve must be moved to the right, away from the motor. To do this, the
right-hand motor must be taken out, together with the reset bar and its three mounting
brackets. Use the follOWing step-by-step procedure:
1. Loosen all set screws in the coupling sleeves on both motors.
2. Take out the screws holding the right-hand motor mounting bracket to the next
bracket.
3. Take out the screws holding the right-hand motor to the mounting bracket.
4. Unplug and remove the motor. Remove the right-hand coupling sleeve from
the reset bar.
5. Take off the reset bar's three mounting brackets and remove the entire assembly.
Take the coupling sleeve off the left-hand reset motor shaft.
6. Now the screws securing the left motor to its mounting bracket and the bracket
to the next bracket can be removed.
7. Unplug and lift out the motor.
To replace the motor, reverse the procedure. Before closing the panel, be sure the
reset bar is positioned so that its blade faces the operator and points downward.
7.4.00 CE PANEL
7.4.01 Indicator Lights
The indicator lights used in the C E panel are identical to those used in the operator's
panel. For information concerning these lights, consult Section 7. 3. 02.
7 . 4. 02 Switches and Receptacles
Switches used on the C E panel are double-throw toggle switches. In addition to these,
there are two Jones plug receptacles into which external keys on cables can be connected.
If the keys are not connected, pins 3 and 4 of the receptacle must be connected together.
This is generally done by means of a special shorting plug.
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IBM 7090 Specifications

General

Category	Mainframe Computer
Introduced	1959
Transistor-based	Yes
Word Length	36 bits
Add Time	4.8 microseconds
Memory	Core memory
Memory (words)	32, 768 words