Tektronix TYPE 109, Инструкция по эксплуатации

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6. Pivot the resistor networks out of the w ay. Lift out the
circuit plate and the switch as a unit (see Fig. 5-1).
W A R N IN G
Mercury and mercury vap or are potential causes
of heavy-m etal poisoning. The mercury switch
consists of a glass envelope co ntaining contacts,
the mercury reservoir, and gas under high pres­
sure. If the g lass is cracked or broken during re­
m oval or replacem ent, the envelope w ill likely
exp lod e. This could produce serious injury due to
fly in g g lass and mercury. Use safety glasses when
you are w orking with the switch.
7. Unsolder the printed circuit plate from the switch ter­
minals.
Install the replacement mercury switch as follows:
1. Check the single terminal located at one end of the
replacement switch. If it is longer than the original switch,
wrap the switch in cloth and cut the terminal for proper
length. Use pliers to round out the cut end of the terminal.
2. Insert the replacement switch into the mercury switch
body and tighten the setscrew near the bottom of the body.
3. Mount the printed circuit plate with the two 2-56 x 'A
RHS screws.
4. Solder the two resistors and the terminals to the printed
circuit plate.
5. Install the bias magnet and V679.
6. Adjust the magnet and the FREQUENCY control for
proper reed operation as described in step 4 of the C alibra­
tion procedure (Section 6).
Maintenance— Type 109
Soldering Precautions
In the production of Tektronix instruments, a special silver­
bearing solder is used to establish a bond to the ceramic
terminal strips. This bond can be broken by the repeated use
of ordinary tin-lead solder, or by the application of too
much heat. Occasional use of ordinary solder will not break
the bond, however, if too much heat is not applied.
If you frequently perform work on Tektronix instruments, it
is advisable that you have a stock of solder containing
about 3% silver. This type of solder is used quite often for
etched circuit boards and should be readily available, it
may also be purchased directly from your Tektronix Field
Engineer in one-pound rolls (part number 251-514).
Because of the slotted terminals in the ceramic strips, you
will probably want to use a wedge-shaped tip on your
soldering iron. A tip such as this allows you to apply heat
directly to the solder in the slot and reduces the amount of
heat required. It is important to use as little heat as is
possible and not to twist the soldering iron. Twisting or
turning the soldering iron in the slot can chip or break the
ceramic strip.
Ceramic Terminal Strips
To remove a ceramic terminal strip, unsolder all com­
ponents and connections, then pry the strip, with yokes
attached, out of the chassis. As an alternative method, use
diagonal cutters to cut off one side of each yoke to free
the strip but try not to damage the spacer.
Ceramic Strip
injmnnj^xnj^
Yoke
i r v -
Notch
t
.................... .......
Chassis
Spacer Yoke Pin
F ig . 5 - 2 . In s ta lla tio n of ce ram ic te rm in a l strip s.
After removing the strip, the remainder of each yoke can
be easily extracted from the chassis with a pair of pliers.
The yokes need not be salvaged since new ones are
furnished with the new strips. If spacers are not damaged,
they may be re-used as long as they hold the strip assembly
securely.
To install a new strip, place the spacers in the chassis
holes, insert the yoke through the spacers, and press down
on top of the strip above the yokes. Use a plastic or hard-
rubber mallet, if necessary, to seat the yokes firmly. Be
sure to tap lightly
above
the yokes and drive them down
in equal increments to keep from placing too great a strain
on the strip. Fig. 5-2 illustrates the w ay the parts fit together.
If desired, the extending portion of the yoke pins can be
cut off to within about ’/0" of the lower end of the spacers.
Use the soldering precautions described earlier when
soldering the leads to the strip.
OBTAINING REPLACEMENT PARTS
Standard Parts
Replacements for all parts used in the Type 109 can be
purchased through your Tektronix Field Office, at current
prices. Many of the components, however, are standard
electronic parts than can usually be obtained locally. Before
purchasing a part, be sure to consult the Parts List to deter­
mine the tolerance and rating required. The Parts List gives
the values, tolerances, ratings and Tektronix part numbers
for all components used in the instrument.
Special Parts
In addition to the standard electronic components men­
tioned in the previous paragraph, special parts are also
used. These parts are manufactured especially for Tektronix
by other companies. These parts and most mechanical parts
should be ordered through your Tektronix Field Office since
they are normally difficult or impossible to obtain from
other sources.
5-2