Tektronix 7B70 Time Base Instruction Manual page 44

TRANSISTORS
Collector Emitter Collector Emitter
Base
Base
R
Collector,
Collector Emitter
UI
Emitter
Base
Base
Collector Collector
Base Base
Emitter Emitter
F.E.T.'s
I N T E G R A T E D
ClRCUlTS
5 4 3
,
Maintenance-7B70 (SN B205000 and Up)
as seen from the bottom of the transistor. When replacing
transistors, check the manufacturer's basing diagram for
correct basing.
Interconnecting Pins and Pin Socket Replacement. Two
types of mating connectors are used for these interconnect-
ing pins. If the mating connector is mounted on a plug-on
circuit board,
a
special socket is soldered into the board. I f
the mating connector is on the end of a lead, a pin connec-
tor is used to mate with the interconnecting pin. The fol-
lowing information provides the replacement procedure for
the various types of pins and pin sockets.
When removing the stub of a broken pin connector, i t
is important not to disturb the old ferrule which is
swaged into the circuit board.
Use
the minimum
amount of heat necessary to remove the pin. The new
pins are supplied with ferrules intact. Remove the
ferrule from the new pin before inserting the pin into
the old ferrule in the circuit board. The old ferrule
may be reamed out with a .031 drill if necessary.
A circuit board pin replacement k i t including neces-
sary tools, instructions and replacement pins is avail-
able from Tektronix, Inc. Order Tektronix Part No.
040-0542-00.
A. CIRCUIT BOARD PINS. To replace a pin which is
mounted on a circuit board, first disconnect any pin con-
nectors. Unsolder the damaged pin and pull i t out of the
circuit board. Press the new pin into the ferrule in the
circuit board. (Notice that the ferrule is not centered on the
pin; be sure the replacement pin
is
positioned in the same
manner a s the original.) Solder the pin on both sides of the
circuit board. If the pin was bent at an angle to mate with a
connector, bend the new pin to match the associated pins.
The inside radius of this bend should not be less .than
0.025
inch.
6. CIRCUIT BOARD PIN SOCKETS. The pin sockets
on the circuit boards are soldered to the rear of the board.
To replace the sockets, first unsolder the socket (use a
vacuum-type desoldering tool to remove excess solder).
Straighten the tabs on the socket to remove
it
from the
hole in the circuit board. Place the new socket in the circuit
board hole and press the tabs down against the board.
Solder the socket tabs to the circuit board.
NOTE
The spring tension of the terminal sockets ensures a
good connection between the circuit board and the
pin. This spring tension can be destroyed by using the
pin sockets as a connecting point for spring-loaded
probe tips, alligator clips, etc.
Fig. 4-3. Electrode configuration of transistors and integrated
C. END-LEAD PIN CONNECTORS. The pin connec-
circuits used in this instrument.
tors used to connect the wires to the circuit board pins are
Scans by ArtekMedia O 2006