Tektronix 465B

Maintenance—465B Service
adjustment of the instrument. When atransistor is replac-
ed, check the
operation
of
the part of
the
instrument
that
may be affected.
Any
replacement
component
should
be of the
original
type or a
direct replacement. Bend
the leads to fit the
socket and cut the leads to the same length as on the
component
being replaced. See Figure
8-1
for basing
diagrams.
To
remove the 14-, 16-, and 20-pin integrated
circuits,
pull slowly and evenly on both ends of the device. Try to
avoid having one end of the
integrated
circuit disengage
from
the socket before the other, since this
may
damage
the pins.
WARNING
Handle silicone grease with care. Avoid getting
silicone
grease in the eyes. Wash hands thoroughly
alter use.
WARNING
|
Voltages
are
present on the exterior surface ol the
chassis-mounted power supply
transistors if power
is applied to the instrument and the POWER switch
in on.
The chassis-mounted
power supply
transistors and
their mounting bolts are insulated from the chassis. In
addition, silicone grease
is
used to
increase heat transfer
capabilities. Reinstall the insulators and replace the
silicone
grease
when
replacing
these
transistors. The
grease should be applied to both sides of the mica
insulators and should be applied to the bottom
side of the
transistor,
where
it comes in
contact with
the
insulator.
NOTE
After replacing a power transistor, check that the
collector is not shorted to ground before applying
power.
INTERCONNECTING PINS. Two methods of inter-
connection
are
used in this
instrument
to
connect the
circuit boards with
other boards and components. When
the interconnection is made
with
a
coaxial cable,
a
special
end-lead connector
plugs
into a socket on
the board.
Other
interconnections are
made
with
a
pin soldered onto
the
board. Two types
of
mating connections are used for
these interconnecting pins. If the mating connector is on
the end
of
a
lead,
an
end-lead pin connector is used which
mates with
the interconnecting pin. I he following infor-
mation provides the replacement
procedure for the
various types of interconnecting methods:
Coaxial-Type
End-Lead Connectors. Replacement of
the
coaxial-type end-lead connectors requires
special
tools and techniques; only experienced maintenance
personnel should attempt
replacement
of these
connec-
tors. It is
recommended that the cable or wiring harness be
replaced as a unit. For
cable
or wiring
harness part
numbers,
see the Replaceable Mechanical Parts List. An
alternative solution is to refer the replacement of the
defective connector
to
your local Tektronix
Field
Office or
representative.
NOTE
A circuit-board
pin-rcpiacemcnt kit including
necessary
tools, instructions, and replacement pins
is available
from Tektronix, Inc.
(see
Maintenance
Aids
information
at the end of
this section).
Circuit
Board Pins. To replace
a
pin which is mounted
on a circuit board, first disconnect any pin connectors,
then, unsolder the damaged pin and pull it out of the
circuit board with a pairof pliers. Be careful nottodamage
the wiring on the board with too much heat. Ream
out
the
hole in the circuit board with a
0.031
" drill bit. Remove the
ferrule from
the
new interconnecting pin and press the
new pin into the hole in the circuit board. Position the pin
in the same manner as
the old
pin,
Then solder the pin on
both
sides
of the
circuit board.
If the
old
pin was bent at an
angle
to
mate with a connector, carefully bend the new pin
to
match the associated pins.
Circuit Board Pin Sockets.
The
pin sockets on the
circuit
boards are soldered
to the
rear of
the board. To
replace one of these sockets, first unsolder the pin (use a
vacuum-type desoldering tool to remove excess solder).
Then straighten the tabs on the socket and remove it from
the hole in the
board. Place
the new socket in the circuit
board
hole
and press the tabs down
against
the board.
Solder
the tabs of
the socket
to
the circuit board; be
careful
not to
get solder into the socket.
NOTE
The
spring tension
of the pin sockets
ensures
a good
connection between the circuit
board
and the pin.
This spring tension can
be
destroyed
by
using the
pin sockets set as a connecting point for spring-
loaded probe
tips,
alligator
clips, or
other devices.
End-Lead Pin
Connectors. The pin connectors used to
connect the wires
to
the interconnecting pins are factory
assembled. They consist of machine-installed pin connec-