Tektronix 442, Инструкция по эксплуатации

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Maintenance—442 Service
5. Pull the attenuator assembly out away from the
Vertical board to disengage the five pin connec­
tors. Then carefully pull the attenuator assembly
toward the back of the 442sotheinput connector
and the AC-GND-DC switch knob will clear the
front panel openings while ensuring that the five
inter-board connector pins do not get bent.
NOTE
The Channel 1 attenuator assembly employs an A5
Shift board to offset its connectors to the location
where the connections are made to the Vertical
board. After the Channel 1 attenuator assembly is
removed from the Vertical board, the Shift board
may be removed from the attenuator assembly by
removing one Phillips-head screw (see Figure 5-8).
6. To re-install the attenuator assemblies and the
Channel 1 Shift board, reassemble in reverse of
the foregoing order. Exercise special care that all
pin connectors are engaged without bending or
breaking them.
Vertical POSITION Control Removal
To remove the vertical POSITION controls, first follow
the foregoing procedure to remove at least one of the
vertical attenuator assemblies to provide access to the
POSITION controls. Then proceed as follows:
1. Remove the appropriate POSITION knob (use a
1/16" Allen wrench).
2. Remove the potentiometer securing nut (use a
5/16" hexagonal socket wrench).
3. Remove the potentiometer from the back of the
front panel (note the lead or plug locations for
reassembly reference) and unsolder the connec­
ting leads or unplug the connector from the
Vertical board.
4. To reinstall the POSITION control, reverse the
order of the foregoing steps.
A8 Vertical Amplifier Board Removal
The attenuator assemblies may remain attached tothe
Vertical board while it is removed. If the attenuator
assemblies are not removed first, they may be removed
later by following the appropriate portions of the steps
under A6 and A7 Attenuator Removal.
Remove the Vertical board as follows:
1. Use a 1/16" Allen wrench to remove all the
VOLTS/DIV and VOLTS/DIV VAR knobs from
their shafts.
2. Perform steps 2 and 3 under A6 and A7
Attenuator Removal.
3. Note locations for reassembly reference and
disconnect all small and large connectors from
the Vertical board.
4. Remove the four screws that secure the Vertical
board to the 442 chassis. (Refer to Figure 5-8 for
location of screws and board assemblies.)
5. The delay line leads may be left connected tothe
Vertical board and the delay line removed along
with the board or the leads may be unsoldered
from the board and the delay line left attached to
the chassis. If the leads areto be unsoldered, note
their positions for reassembly reference, un­
solder the four leads, and remove the two screws
to unfasten the delay line cable from the Vertical
board (use a Phillips-head screwdriver; it may be
necessary to partially raise the Vertical board
away from the chassis and hold the nuts with a
socket wrench or plier while unfastening these
screws). If the delay line is to be left connected to
the Vertical board, removethethree Phillips-head
screws that securethe delay line assembly tothe
chassis.
6. Lift the Vertical board assembly toward the back
and away from the 442 chassis. If the attenuator
assemblies were left attached to the Vertical
board, guide the input connectors, attenuator
shafts, and AC-GND-DC switch knobs back out
of the front panel openings. Make sure that all
wires, cables, and connectors are free of the
Vertical assembly as it is being removed.
7. If the attenuator assemblies and Shift board need
to be removed and haven’t already been removed,
refer to A6 and A7 Attenuator Removal for
instructions on completion of their removal from
the Vertical board assembly.
8. To reinstall the Vertical assembly, reverse the
order of the foregoing procedure.
5-18
REV A MAY 1980