Section 4 —475
MAINTENANCE
Cabinet Removal
W A R N I N G
I
Dangerous potentials exist a t several points through
out this instrument. When the instrument is operated
with the cover removed, do not touch exposed
connections or components. Some transistors may
have elevated cases. Disconnect power before cleaning
the instrument or replacing parts.
The instrument wrap-around cabinet can be removed in
the following manner:
1. Unwrap the power cord from the instrument feet.
2. Remove the six screws indicated in Fig. 4-1 and
remove the instrument feet and rear ring assembly from the
instrument.
3.
Slide the wrap-around cabinet to the rear and remove
the oscilloscope.
To replace the instrument in its wrap-around cabinet,
reverse the removal procedure. The portable wrap-around
cabinet should be installed with the carrying handle pivot
points positioned toward the bottom of the instrument.
P R E VE N TIV E M A IN TEN A N C E
General
Preventive maintenance consists primarily of cleaning
and visual inspection. When performed on a regular basis,
preventive maintenance can prevent instrument breakdown
Fig. 4-1. Removing wrap-around cabinet.
and will improve the reliability of this instrument. The
severity of the environment to which the 475 is subjected
will determine the frequency of maintenance. A convenient
time to perform preventive maintenance is just prior to
recalibration of the instrument.
Cleaning
General. The 475 should be cleaned as often as opera
ting conditions require. Accumulation of dirt in the
instrument can cause overheating and component break
down. D irt on components acts as an insulating blanket and
prevents efficient heat dissipation. It also provides an
electrical conduction path which can result in instrument
failure.
The cabinet provides protection against dust in the
interior of the instrument. Operation without the cabinet in
place necessitates more frequent cleaning. The front cover
provides a measure of dust protection for the front panel
and the CRT face. The front cover should be installed when
storing or transporting the instrument.
Avoid the use o f chemical cleaning agents which
might damage the plastics used in this instrument.
Avoid chemicals which contain benzene, toluene,
xylene, acetone or similar solvents. Recommended
cleaning agents are isopropyl alcohol or Kelite (1 part
Kelite, 2 0 parts water).
Switch Contacts. Most of the switching in the 475 is
accomplished with circuit-board mounted, cam-actuated
contacts. Care must be exercised to preserve the high-
frequency characteristics of these switches. Seldom is
switch maintenance necessary, but if it is required, observe
the following precautions.
Cleaning the switch contacts should only be done using
isopropyl alcohol or a solution of one part Kelite to 20
parts water. In the absence of these cleaners it is safe
to use petroleum ether, white kerosene, or a solution of 1%
Joy detergent and 99% water. Do not use acetone, MEK,
M IBK , benzol, toluol, carbon tetrachloride, trichlor, tri-
chlene, methyl alcohol, methylene chloride, sulfuric acid,
or Freon TC-TE-TF-22-TA -12.
®
4-1
Summary of Contents for 475
Page 6: ...475 475 Oscilloscope ...
Page 20: ......
Page 46: ......
Page 151: ...A B C D E F G Fig 7 4 P 0 A4 Vertical Mode Switch circuit board ...
Page 152: ...n m m m 1 t siumm c ii im ...
Page 154: ...Diagrams 475 A B C D E F G ...
Page 155: ...GRID LOCATOR Fig 7 8 P O A3 Vertical Preamp circuit board ...
Page 157: ...Diagrams 475 ...
Page 158: ...GRID LOCATOR 2 3 4 5 6 7 8 9 1 10 11 1 12 Fig 7 10 P 0 A3 Vertical Preamp circuit board ...
Page 160: ...Diagrams 475 GRID LOCATOR Fig 7 11 A5 Vertical Output circuit board ...
Page 163: ...Diagrams 475 GRID LOCATOR Fig 7 12 P O A8 Trigger Generator And Sweep Logic circuit board ...
Page 167: ... 415 OSCILLOSCOPE B T R IG G E R G E N E R A T O R g B TR IG G E R GEN ER A TO R ...
Page 168: ...Diagrams 475 GRID LOCATOR ...
Page 172: ...SWEEP G E N ER A TO R S ...
Page 175: ...TIM IN G HORIZONTAL DISPLAY SWITCHING ...
Page 177: ...A 011 HORIZONTAL AMPLIFIER 8 l j k J Ll J Ol Z o N C O X U 1 C L O o v O o _J V v P O in r ...
Page 179: ... 476 OSCILLOSCOPE ...
Page 180: ...POWER SUPPLY ...
Page 182: ...CRT CIRCUIT ...
Page 185: ...C A L IB R A T O R A N D F A N C I R C U I T 4 C A LIB R A TO R FAN MOTOR C IR C U IT ...
Page 189: ......
Page 190: ...4 T 475 OSCILLOSCOPE FIG 1 FRO NT PANEL ...
Page 191: ...475 OSCILLOSCOPE FIG 2 MAIN FRAME ...
Page 199: ......
Page 200: ...FIG 3 RIGHT SIDE l 475 OSCILLOSCOPE ...
Page 201: ...V S X O t l B O T T OVJ 8 8 ...
Page 209: ......
Page 210: ...5 ...
Page 211: ...4 4 75 O S C ILLO S C O P E FIG 5 CAB IN ET ...
Page 215: ......
Page 237: ......
Page 241: ... 1 I R I II9A po S IT I o n f i n e I R l 130 PAGE 4 OF 5 R 1234 Ml 9 91 9 473 ...