Tektronix 543B Instruction Manual page 22

Maintenance — Type 543B /R M 543B
Fig. 4-1, Fan motor lubrication points.
The following procedure is recommended when soldering
to ceramic terminal strips:
1. Use a wedge-shaped soldering-iron tip about '/a inch
wide. This allows heat to be applied directly to the
solder in the terminal strip, thereby reducing the amount
of heat required.
2. Maintain a dean, properly tinned tip.
3. Use a hot iron for a short time. A 50- to 75-watt iron
having good heat transfer and storage characteristics
is adequate.
4. Avoid putting pressure on the strip. Excess pressure may
crack or chip the strip.
5. Apply only enough heat to make the solder flow freely.
6. Do not attempt to fill the notch on the strip with solder;
instead apply only enough solder to cover the wires
adequately and establish a solid solder joint. Overfill­
ing the notches may result in cracked terminal strips.
If the lead extends beyond the solder joint, clip the
excess as close to the joint as possible.
wire clippings from the chassis.
When soldering to metal terminals (e.g., pins on a tube
socket or terminals on a switch) a slightly different tech­
nique should be used. Prepare the iron as described
4-2
previously and apply the iron to the junction to be soldered.
Use only enough heat to allow the solder to flow freely
along the wire so that a solid solder joint is formed. Ex­
cessive solder and/or heat may cause the solder to run
into the tube socket or onto the switch contacts and ruin
the part; whereos, inadequate heat will result in a poor
electrical connection.
-
N^ - R T ¥
C hassis^
Fig. 4-2. Ceramic strip assembly.
Ceramic Terminal Strips
Fig. 4-2 shows an assembled ceramic terminal strip. Re­
placement strips with studs attached are supplied under
one part number; the spacers are supplied under a sep­
arate part number. However, the old spacers may be re­
used if not damaged.
Usually a strip can be pried out of the chassis or pulled
out with a pair of pliers. If desired, a hammer and punch
may be used to drive out the studs from the opposite side
of the chassis.
When the damaged strip has been removed, place the
new or used, but undamaged, spacers in the chassis holes.
Then, carefully force the studs of the new strip into the
spacers until they are completely seated. If necessary, use
a soft-faced mallet and tap lightly directly over the stud
area of the strip.
Component Replacement
Certain parts in the instrument are easiest to replace by
following a definite procedure.
placing these parts are outlined in the following para­
graphs.
Many electrical components are mounted in a particular
manner to reduce or control stray capacitance or induc­
tance. Attempt to duplicate the original location and mount­
ing when replacing components. When selecting replace­
ment parts, remember that the physical nature of a com­
ponent can affect its performance at high frequencies.
Remove all
After repair, check the instrument calibration.
Turn o ff the instrument power before replacing
transistors or other components.
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S pacer ^ > S h j d
The procedures for re­
WARNING
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Pin