Tektronix 502 series, Инструкция по эксплуатации

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Fig. 5 -1. Removal of the instrument side panels.
fore laying the instrument on its side. The bottom
panel should then be removed last. Panels are
replaced by reversing the order of their removal.
Replacement of the Cathode-ray Tube
To remove the cathode-ray tube, first discon­
nect the tube socket and all leads connected to
the neck of the tube. Loosen the tube clamp at
the base of the crt and remove the graticule
cover. Pull the crt straight out through the front
panel. When the new crt is in place, the leads
may be properly connected to the neck of the
tube by following the color code information
provided on the tube shield. After replacement
of a crt, it will be necessary for you to recali­
brate the oscilloscope.
Replacement of Switches
Methods for removal of defective switches are,
for the most part, obvious and only a normal
amount of care is required. Single wafers are
normally not replaced on the switches used in
the Type 502 and if one wafer is defective, the
entire switch should be replaced. Switches may
be ordered from Tektronix either wired or un­
wired as desired.
Tube Replacements
Care should be taken both in preventive and
corrective maintenance that tubes are not re­
placed unless they are actually causing a definite
circuit malfunction. Many times during routine
maintenance it will be necessary for you to re­
move tubes from their sockets. It is important
that these tubes be returned to the same sockets
Fig. 5-2. The method for removal and replacement of
the crt.
unless they are actually defective. Replacement
or switching of tubes will many times necessitate
recalibration of the instrument. If tubes do re­
quire replacement, it is recommended that they
be replaced by previously checked high quality
tubes. Low noise tubes used in the instrument
should be replaced by equivalent tubes.
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
may be broken by repeated use of ordinary tin-
lead solder, or by the application of too much
heat.
However, occasional use of ordinary
solder will not break the bond if too much heat
is not applied.
It is advisable that you have a stock of solder
containing about 3% silver if you frequently per­
form work on Tektronix instruments. This type of
solder is used quite often in printed circuitry and
should be readily available. It may also be pur­
chased directly from Tektronix in one-pound rolls
(order by part number 002-664).
Because of the shape of the terminals on the
ceramic terminal strips you may wish 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 terminals thereby reducing the
heat required to melt the solder. Since excessive
heat can destroy the bond of the terminal to the
ceramic material, it is important to use as little
heat as possible. Also, the wedge-shaped tip is
desirable from a convenience stand-point, since
it is easier to work on the ceramic strips with
this type of tip.
5-2
MAINTENANCE — TYPE 502