Replacement; Switches; Semiconductors; Interconnecting Pins - Tektronix 7B85 Instruction Manual

Maintenance-/B85
Switches
°I°wo types of switches are used in this instrument . Con-
tact alignment and spacing are critical to the operation of
the push button and cam switches . Therefore, defective
switches should either be replaced as a unit or repaired only
by personnel experienced with these types of switches .
Your local Tektronix Field Office or representative can pro-
vide additonal repair information . The following special
maintenance information is provided for switch replacement .
Carry Switches. Cam switches consist of a rotating cam
that mates with contacts on the adjacent circuit board .
These contacts are activated by lobes on the cam as the
switch is rotated. A cam switch can be disassembled for
inspection, cleaning, repair, or replacement ; however, it is
recommended that the switch be removed and replaced as
a unit . Refer to Fig . 4-9 for special instruction on cam switch
removal.
An extraction tool should be used to remove the 14- and
C A U 1r I O N 16-pin integrated circuits to prevent damage to the pins .
,. ... This tool is available from Tektronix, Inc . Order Tektronix
Part No . 003-0619-00. If an extraction tool is not available
Repair of a cam switch should be undertaken only by
when removing one of these integrated circuits, pull slowly
experienced maintenance personnel. Switch align-
and evenly on both ends of the device . 'f"ry to avoid having
meet and contact spacing must be carefully main-
one end of the integrated circuit disengage from the socket
tained for proper operation. A cam switch repair kit is
before the other, as the pins may be damaged.
available (Tektronix part No . 040-0541-00) that con-
tains special alignment tools for use in repairing or
replacing the switch contacts. For information or as- Interconnecting Pins
sistance on maintenance of cam switches, contact
your local Tektronix F7eld Office or representive.
Three methods of interconnection are used to connect
the circuit boards with other boards and components . When
the interconnection is made with a coaxial cable, a special
Push-Button Switches . Removal and replacement
end-lead connector plugs into a socket on the board (Fig .
instructions for push button switches are shown in Fig.
4-8) . When the interconnection is made with a wire lead, an
4-10 .
end-lead connector is used that mates with the
interconnecting pin soldered into the board (Fig . 4-4) . When
the interconnection is made between adjacent boards, an
Semiconductors
interboard multi-pin connector is used (Fig . 4-3) . The follow-
ing information provides the removal and replacement pro-
cedure for the various types of interconnection methods.
C A U °P I O N ~
Coaxial End-Lead Connectors . Replacement of the co-
~^^^~~^^~~^^
axial-type end-lead connectors requires special tools and
techniques ;
only
experienced maintenance personnel
To avoid component damage, power must be turned
should attempt to remove and replace these connectors . It
otf before removing or replacing semiconductors. is recommended that the cable be replaced as a unit . For
cable part numbers, see the Replaceable Mechanical Parts
list . An alternative solution is to refer the replacement of the
Semiconductors should not be replaced unless actually defective connector to your local Tektronix Field Office or
defective. If semiconductors are removed during routine representive .
maintenance, return them to their original sockets. Unnec-
essary replacement of semiconductors may affect the ad-
justment of this instrument . When semiconductors are End-Lead Pin Connectors . The pin connectors used to
replaced, check the operation of the part of the instrument connect the wires to the interconnecting pins are clamped to
that may be affected . the ends of the associated leads . To remove and replace
4-1~ REV AUG 1981
WARNING
Handle silicone grease with care . Avoid getting sili-
cone grease in eyes. Wash hands thoroughly after
use.
Replacement devices should be of the original type or a
direct replacement. Figure 4-2 shows the lead configura-
tions of the semiconductor devices used in this instrument .
Some plastic-case transistors have lead configurations that
do not agree with those shown here . When replacing, check
the manufacture's basing diagram for correct basing . All
transistor sockets in this instrument are wired for the stan-
dard basing used for metal-case transistor . Semiconductors
that have heat radiators use silicone grease to increase heat
transfer . Replace the silicone grease when replacing these
semiconductors .