Tektronix 535A, Инструкция по эксплуатации

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Maintenance — Type 535A
NOTE
Whenever the transformer is connected to operate
on nominal primary voltages in the 216 to 244 volt
range, the fan wiring must be changed.
parts changes, we recommen d that you keep on hand a stock
of solder containing about 3% silver. This type of solder is
used frequently in printed circuitry and should be readily
available from radio-supply houses. If you prefer, you can
order the solder directly from Tektronix in one-pound rolls.
Order Tektronix part number 251-514.
Visual Inspection
You should visually inspect the entire oscilloscope every
few months for possible circuit defects. These defects may
include such things as loose or broken connections, dam­
aged binding posts, impro perly seated tubes, scorched wires
or resistors, missing tube shields, or broken terminal strips.
For most visual troubles the remedy is apparent; however,
particular care must be taken when heat-damaged com-
AC AC
Because of the shape of the terminals on the ceramic
strips it is advisible to use a wedge-shaped tip on your
soldering iron when you are installing or removing parts
from the strips. Be sure to file smooth all surfaces of the iron
which will be tinned. This prevents solder from building up
on rough spots where is will quickly oxidize.
When removing or replacing components mounted on the
ceramic strips you will find that satisfactory results are ob­
tained if you proceed in the manner outlined below.
1. Use a soldering iron of about 75-watt rating.
2. Prepare the tip of the iron.
3. Tin only the first 1/16 to '/8 inch of the tip. For solder­
ing to ceramic terminal strips tin the iron with solder con­
taining about 3% silver.
4. Apply one corner of the tip to the notch where you
wish to solder.
5. Apply only enough heat to make the solder flow freely.
Fig. 5-4. 535A, below SN 32772: Power transformer connections
for nominal 117 V or 234 V, 50 to 60 Hz input voltage.
ponents are detected. Overheating of parts is often the result
of other, less apparent, defects in the circuit. It is essential
that you determine the cause of overheating before replac­
ing heat-damaged parts in order to prevent further damage.
Soldering and Ceramic Strips
Many of the components in your Tektronix instrument are
mounted on ceramic terminal strips. The notches in these
strips are lined with a silver alloy. Repeated use of exces­
sive heat, or use of ordinary tin-lead solder will break down
the silver-to-ceramic bond. Occasional use of the tin-lead
solder will not break the bond if excessive heat is not applied.
If you are responsible for the maintenance of a large num­
ber of Tektronix instruments, or if you contemplate frequent
Fig. 5-5. Correct method of applying heat in soldering to a ceramic
strip.
6. Do not attempt to fill the notch on the strip with solder;
instead, apply only enough solder to cover the wires
adequately, and to form a slight fillet on the wire as
shown below.
5-3