Tektronix T922 - Page 78

Service
Information-T921/T922/T922R
WARNING
The crt
anode and the high-voltage multiplier will
hold a charge after you turn
off the instrument . To
prevent a shock hazard,
use only one hand to
remove the anode lead . Then,
touch the anode lead
to one of the posts to discharge the crt
(see
Fig .
5-
12) .
Also, take a short piece of insulated wire
and
short the
output of the high-voltage multiplier
to
the
chassis
(see Fig . 5-12) .
3 . Slide the crt
anode lead out from under the plastic
clip which holds it next
to
the
chassis near the interface
board .
4 . Make note of the
positions of the four crt leads to aid
in reassembly . Remove the four crt
leads from the neck of
the crt
.
5 . Remove
crt socket from the base of the crt .
6 . Lift the plastic mask
and light filter away from the crt
to remove .
After
you remove the bezel, the crt can slide forward .
To avoid crt
damage, hold one hand over the crt face
if you must turn or
move the instrument .
7 .
Remove the four screws holding the
bezel . Lift the
bezel and
implosion shield away from the crt .
8 . Remove the graticule
illumination assembly .
9 .
While holding one hand over the
crt face, push the
base
of
the
crt forward . When you are able, firmly
grasp the
front of the crt
and slide it out of the crt shield assembly
.
SCALE ILLUM Lamp
Replacement
1 . Lift the plastic
mask and light filter away from crt to
remove .
2 .
Disconnect P816 from the SCALE ILLUM assembly .
3 . Pull SCALE ILLUM
assembly away from the crt to
remove . If this is difficult, push
against the
two
screws
from behind the front panel (see Fig . 5-14) .
4
.
Remove the two screws holding the plastic piece to
the circuit board . Remove the plastic piece .
5 . Unsolder the defective lamp and replace .
Fuse Replacement
WARNING
Line voltage is present on the fuse whenever the
power cord is plugged in . To prevent a shock hazard,
disconnect the power cord .
The fuse is located in a holder near the rear
of
the
interface board . To remove, grasp firmly and pull away
from the interface board .
Fig . 5-14 . T922R scale illum
assembly replacement .