IBM 7090 User Manual

7 . 3. 03 Unitized Assembly Lights and Keys
Unitized assemblies use telephone-type lights. Some operate on 48 volts and some
on 6 volts. Be sure to use the correct replacement for each bulb.
Removal and Replacement
To remove the plastic cover over the light or key assembly, press in on one side of
the cover and work it out of its holder. The light bulb is removed by grasping it on the
end and pulling straight out. To replace, reverse the procedure.
7.3.04 Switches and Keys
To
gain access to the switches and keys on the operator's panel, the panel must be
tilted up. To do this, three latches must be released. Release the latches by inserting
a screw driver in each latch hol~\ one after the other, and pressing in. The latch holes
are located across the front, underneath the shelf.
Adjustment
It may become necessary to adjust the switches so that the reset motor will retur~
all of them to the OFF position at the same time. The switches can be adjusted up or
down and in or out. Usually best results will be obtained if the bottom nut is lowered
as close to the base of the switch as is possible. In this way the switch lever is brought
as deeply as possible into the plastic rocker.
Removal and Replacement
To remove a switch, it may be necessary to loosen the bar upon which all the switches
are mounted. This bar is held by two screws at either end. Removing the bar will not
affect the plastic rockers, for they are held by a single shaft which is independent of
the switches.
7.3.05 Plastic Rockers
Plastic rockers are used to actuate toggle switches mounted underneath the panel.
They may require replacement if they become chipped or broken.
Removal and Replacement
Removal of one or more plastic rockers requires the removal of the assembly upon
which all the toggle switches are mounted. Two nuts at either end are removed to take
off the assembly. The shaft on which the rockers are strung can then be pulled out and
any or all of the rockers can be taken off. New roc1q3rs may then be slipped on the
shaft and the shaft put back in its proper place on the panel.
7 . 3. 06 Reset Motor
There are two 115-volt reset motors in the console, one whose shaft rotates 60 rpm
clockwise, and the other 60 rpm counterclockwise. A manufacturer's part number is
stamped on each motor. The number ending in the letter J identifies the right-hand
motor. The left-hand motor is stamped with a number ending in the letter K.
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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