SECTION
4
MAINTENANCE
PREVENTIVE MAINTENANCE
Air Filter
Care
must be taken to assure free ventilation of the
Type
502A
inasmuch as some of the components are oper
ated
at dissipation levels
such
that excessive interior
temperatures
will
result without adequate
air circulation.
To
assure
free passage of air the instrument must be placed
so
that
the air intake is not blocked and the filter must be
kept clean. Moreover,
the side panels and bottom cover
must be in
place
for proper air circulation. Do not remove
the covers
except
during maintenance.
A washable filter
is
used at the air intake part
of the
instrument.
Under
normal operating conditions the filter
should
be inspected and cleaned
if necessary every three
to four
months. More frequent inspection is
required when
the
operating
conditions are more severe.
The
following cleaning procedure is suggested:
1.
Flush
loose dirt out of filter with a
stream of hot water.
2. Prepare
a
hot water and mild soap or
detergent
solution. Wash the
filter as you would wash a sponge so
that
the
adhesive
and dirt
is loosened and floated off.
3. Rinse
the filter and let it dry.
4. Dip or
spray
filter
with fresh Filter Coat or Handi
Coater.
These
products are available from the local repre
sentative
of
the Research Products Corporation and from
most
air conditioner suppliers.
Fan
Motor
The
fan motor bearings are sealed and should not
require lubrication for
the life of the
motor.
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, damaged
binding
posts,
improperly 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
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
replacing heat-damaged parts in order to prevent
further
damage.
Soldering and Ceramic
Strips
Many
of the components in your Tektronix
instruments
are
mounted
on ceramic
terminal strips. The notches in
these
strips
are lined with a silver alloy. Repeated use of
excessive
heat, or use of ordinary tin-lead solder will break
the
silver-to-ceramic bond. Occasional
use of tin-lead solder
will
not
break the bond if excessive heat is not applied.
If you are
responsible
for the maintenance of a large
number
of Tektronix instruments, or if you contemplate
frequent parts changes, we
recommend 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
by Tektronix part number 251-514.
Fig.
4-1. Soldering iron tip properly shaped and tinned.
Because of
the shape of the terminals on the ceramic
strips
it is advisable to use a
wedge-shaped tip on your
soldering
iron
when
you are
installing or removing parts
from
the strips. Fig. 4-1 will show you the correct shape
for
the
tip of the soldering iron. Be sure to file smooth all
surfaces
of the iron which
will be tinned. This prevents
solder
from
building up on rough
spots where it will
quickly oxidize.
When
removing
or replacing components mounted
on the
ceramic
strips you will find that satisfactory results are
obtained
if you proceed in the
manner outlined below.
4-1
Summary of Contents for 502A
Page 4: ......
Page 22: ...Circuit Description Type 502A Fig 3 2 Simplified Sweep Trigger Circuit t i CO ...
Page 27: ...Circuit Description Type 502A Fig 3 4 Simplified Horizontal Amplifier 3 9 ...
Page 32: ...Circuit Description Type 5O2A Fig 3 7 Simplified Calibrator Circuit 3 14 ...
Page 34: ...NOTES ...
Page 56: ...NOTES ...
Page 60: ...Parts List Type 502A LEFT SIDE 6 4 ...
Page 64: ...Parts List Type 502A RIGHT SIDE 6 8 ...
Page 67: ...Parts List Type 502A TOP 6 11 ...
Page 70: ...Parts List Type 502A BOTTOM 6 14 ...
Page 73: ...Parts List Type 502A REAR 6 17 ...
Page 89: ...TYPE 502A OSCILLOSCOPE A ...
Page 90: ...A BLOCK DIAGRAM MRH Z6 3 ...
Page 91: ... TYPE 502A OSCILLOSCOPE A ...
Page 92: ...A CIRCUIT NUMBERS 1 THRU 59 I Ixj 263 TIME BASE TR IGGER ...
Page 93: ......
Page 95: ...TI M I NG RESI 5TORS TIMING CAPACITORS TYPE 502A OSCILLOSCOPE ...
Page 96: ...SWI6O HOLD OFF CAPACITORS 4 RESISTORS TIM ING CAPACITORS o A TIMING SWITCH job ...
Page 98: ... 1 INPUT AMPLIFIER OUTPUT AMPLIFIER A CIR CUIT NUMSER 5 300 THR U 399 ZG3 joe ...
Page 100: ...CMO 363 VERTICAL ATTENUATOR SWITCH A ...
Page 103: ...TYPE 5O2A OSCILLOSCOPE OOM HEATER WIRING DIAGRAM ...
Page 104: ...POWER SUPPLY CIRCUIT NUMBERSI 600 THRU 799 ...
Page 106: ...CIR CUIT NUMBER S 800 THR U 869 CRT CIRCUIT c 9G4 ...
Page 107: ...CA LIBp A TOp MULTIVIBP A TOR 1 IOOV o TYPE 5O2A OSCILLOSCOPE A ...
Page 108: ...CAL OUT CF CALIBRATOR A CIRCUIT NUMBERS 8 7O THRU 899 4Z ...