Maintenance—7D14
3.
Using
a
7/16-inch
open-end
wrench,
loosen
the nut
securing the coaxial-cable
connector to the rear of the CH
A
INPUT
BNC connector.
4. Slide the nut over
the
coaxial-cable connector toward
the
circuit
board.
5.
Remove
the
board from the unit while sliding the
coaxial-cable connector
from the
BNC connector.
6.
To
replace the board, first install the coaxial-cable
connector
in the
BNC connector.
7.
Position
the
board
so the securing-screw holders mate
with
the guide posts.
8.
Gently
press the circuit board while making sure that
all
of
the
interconnecting
pins and sockets mate properly.
Switch
Replacement
Two
types of switches are used in the 7D14, pushbutton
and
rotary. If a switch is defective, it must be replaced as a
unit.
Observe
normal soldering precautions when replacing
these switches.
See the information under Light-Bulb
Replacement
for
instructions on
replacing the light bulbs.
Illustrations
of the pushbutton switches
and the wiring
color
code
are given
on the backs of pull-out pages in the
Diagrams
section. Use the following procedures to replace a
front-panel
switch :
A
Pushbutton Switch Replacement
1.
Remove
the
knobs from
the LEVEL/SLOPE, INPUT
SENS,
and DISPLAY TIME control shafts. Use a 1/16-inch
hex-key wrench.
2.
Remove
the
front panel from the instrument.
3.
Disconnect
the associated multi-pin connector(s)
from
the
circuit board.
9.
Uniformly
tighten
the
securing
screws.
Recommended
torque, four to six inch-pounds.
10.
Tighten
the nut on the rear of the CH A INPUT
connector.
B.
LOGIC
AND CONTROL CIRCUIT BOARD REPLACE
MENT.
1.
Remove the
High Frequency
Counter circuit board
following
the procedure given under A.
4.
Remove
the
defective unit.
5.
Disconnect the wires from the switch circuit board.
6. To replace, reverse
the
order of removal.
B
Rotary Switch
Replacement
1.
Before
replacing the defective unit, draw a sketch
of
the terminals showing the wire
color code to each terminal.
2.
Remove
the springs and metal shield from the
securing-screw
guide
posts.
3.
Disconnect the multi-pin connectors from the circuit
board.
2.
Disconnect the
wires from the terminals.
3.
Remove the
knob from the control shaft. Use a
1/16-inch hex-key wrench.
4.
Remove
all the screws holding the board to the chassis
or
other
mounting
surface.
5.
Remove the screws holding the plastic plug-in guide to
the top and bottom frame
sections.
6.
Remove
the
board from the unit and from the plastic
guide.
Do not force or bend the board.
7.
To replace
the board,
reverse the order of removal.
4.
Remove
the defective unit from
the instrument.
5.
To
replace, reverse the
order of
removal.
S
CAUTION <
When
disconnecting or
connecting leads to a wafer
type rotary switch,
do not let solder flow around and
beyond
the rivet on the switch terminal.
Excessive
solder
can destroy
the spring tension of the contact.
4-5
Summary of Contents for 7D14
Page 4: ...7D14 ...
Page 11: ...Operating Instructions 7D14 Fig 2 1 7D14 front panel controls and connectors 2 2 ...
Page 33: ... 3 13 Fig 3 11 Logic diagram for Zero Cancel Logic stage Circuit Description 7D14 ...
Page 38: ...3 18 Fig 3 16 Time Base and Control circuit detailed block diagram Circuit Description 7D14 ...
Page 44: ...NOTES ...
Page 46: ...NJ Fig 4 1 Electrode configuration for semiconductors in this instrument I ...
Page 68: ...NOTES ...
Page 96: ... 7DI 4 DIGITAL COUNTER UNIT ...
Page 98: ...GRS 0371 BLOCK DIAGRAM ...
Page 99: ......
Page 103: ...0 0 I 200 mV 500 µs 0 001 200 mV 500 µs 0 001 MHz 00 mV E 00 µs 0 001 MHz ...
Page 106: ...1 ...
Page 110: ...A2 Logic Circuit Board Assembly jQ798i 798 jc743 CR744t uni R724 R742 JL744S FrR796 ...
Page 113: ......
Page 114: ...P 0 A2 LOGIC BOARD ...
Page 121: ... A B D t F H J NPR Tj ZWX V A AC M AEA HUM qAZ DEF HJ N P R S T J V V7X y ABM APAI AA 7DI4 ...
Page 129: ......
Page 130: ...4 7D14 DIGITAL COUNTER ...