Tektronix 2215A, Instruction Manual

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Maintenance— 2215A Service
13. Reinstall the collet and the B SEC/DIV knob at the
position noted in step 2 and secure it with the nut.
14. Reinstall the SEC/DIV Variable knob onto its shaft
(with lettering horizontal and right-side up) and tighten the
set screw.
Bottom Shield, Attenuator and Timing Circuit-
Board Module
Removal of the module consisting of the Bottom shield
and the Attenuator and Timing circuit boards is accom­
plished by the following steps:
1. Perform steps 1 through 5 under the “Attenuator Cir­
cuit Board” removal procedure.
2. Perform steps 1 through 4 under the “Timing Circuit
Board” removal.
3. Place the instrument on its side and remove four
screws holding the Bottom shield to the Main circuit board.
4. Pull the Bottom shield, along with the Attenuator and
Timing circuit boards straight back from the front of the in­
strument until the interconnecting pins on both circuit
boards are disengaged and the switch shafts are clear of
the holes in the Front-Panel circuit board; then lift out the
entire assembly through the top of the instrument.
5. If accessibility to the bottom of either the Attenuator
or the Timing circuit board is desired, refer to steps 6 and 7
of the “Attenuator Circuit Board" removal procedure and to
steps 5 and 6 of the “Timing Circuit Board” removal
procedure.
To reinstall the Bottom shield-Attenuator-Timing assem­
bly, perform the following steps:
6. If one or both of the circuit boards was removed, rein­
stall the circuit board(s) to the Bottom shield by referring to
steps 10 and 11 of the “Attenuator Circuit Board"
reinstallation procedure and to steps 9 and 10 of the “Tim­
ing Circuit Board" reinstallation procedure.
7. Insert the three switch shafts through the holes in
both the Front-Panel circuit board and the front panel (refer
to the "Attenuator Circuit Board" and the “Timing Circuit
Board" reinstallation procedures).
8. Reinstall the four screws holding the Bottom shield to
the Main circuit board (removed in step 3).
9. Complete reinstallation of the module by performing
steps 12 through 17 of the “Attenuator Circuit Board”
reinstallation procedure and steps 11 through 14 of the
“Timing Circuit Board" reinstallation procedure.
Front-Panel Circuit Board
1. Remove the crt (see the “Cathode-Ray Tube” removal
procedure).
2. Remove the Bottom shield, Attenuator, and Timing
circuit-board module (see the preceding removal procedure).
3. Remove the knobs from the following control shafts
by pulling them straight out from the front panel:
a. Channel 1 and Channel 2 POSITION,
b. A/B SWP SEP,
c. Horizontal POSITION,
d. A TRIGGER LEVEL,
e. B TRIGGER LEVEL.
4. Unsolder both the resistor to the EXT INPUT center
connector and the wire strap to the EXT INPUT ground lug.
5. Unsolder the single wire from the PROBE ADJUST
connector and the two wires from the VAR HOLDOFF con­
trol (leading to the Front-Panel circuit board).
6. Remove the following screws:
a. Three screws securing the upper part of the Front-
Panel circuit board to the front panel.
b. Two recessed frame-securing screws at the left-rear
corner of the chassis frame.
c. Two screws holding the Main circuit board to the
chassis frame.
d. One screw securing the delay line to the chassis
frame on the left side of the instrument.
e. Two recessed frame-securing screws at the right
front corner.
7. Pull the front-left frame assembly apart from the rear-
right frame assembly.
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