Tektronix 4010 Maintenance Manual page 45

Install the yoke-mounting bracket or shield, as appro-
priate, in place on the center wall. Leave the nuts loose
enough to permit the yoke to align with the neck of the
CRT during replacement.
CRT Installation. At each side, loosen (don't remove)
two screws which hold the center wall in place, permitting
the wall to be moved easily. Then position the wall so that
the neoprene bumpers on the front of the CRT shield are
just started past the tangs on the cabinet. Re-tighten the
two screws at each side of the center wall.
Insert the CRT and attached neoprene mounting ring
into the display unit cabinet, carefully aligning the neck
with the yoke. Avoid side pressure on the neck. With the
CRT partially inserted, a second person should feed the
deflection plug and cable through the top or bottom,
depending upon whether the CRT is inserted with the
deflection cable on the top or on the bottom.
This paragraph pertains only to the early version of the
frame assemblies in which the corner clips are separate from
the frame. Remove the corner clips from the frame. Place a
corner clip on each screw attached to the cabinet near each
corner of the face of the CRT. The plane containing the
hole should be outermost, with the lip aligning with the
step in the neoprene mounting ring. See Fig. 3-4. (The clips
may be difficult to align at this time, but will be adjusted as
necessary in a later step.)
E3
During the fol/owing procedure, the neck shield
mounting nuts must be loose enough for the assembly
to move around easily, avoiding pressure on the neck.
Remove the filter and the two angle brackets from the
frame. The angle brackets are held in place by screws at
each end.
Put the frame in place, fitting it over the neoprene
mounting ring. Install it carefully to avoid distorting the
neoprene mounting ring. If necessary, slide the CRT
forward slightly to make it easier to install the frame.
Fig. 3-4. Positioning of Corner Clips.
®
Servicing-4010 Maintenance
While holding the frame in place, install the four spacer
sleeves over the corner screws, aligning the sleeves with the
frame, clips, and screws as required. It may be necessary to
lift up on the bottom of the frame. If the early version of
the frame is installed, it may be necessary to adjust the clips
while installing the spacers.
Start the nuts onto the top screws. then place the nuts
on the bottom screws, pressing in and up on the bottom of
the frame as necessary.
If the early version of the frame is installed, check that
the clips at the bottom corners are properly in place,
extending over the step in the neoprene ring; then push
each clip as far toward the corner as possible and tighten
the bottom nuts. Repeat at the top corners. If the latest
version frame is installed (corner clips fastened to the
frame), simply tighten the four nuts, drawing them up
evenly.
Check the alignment of the CRT with the display unit
cabinet. The edge of the display area should be parallel with
the top edge of the display unit frame. If it isn't, loosen the
corner nuts slightly, adjust the CRT, and retighten.
Using a soft cloth and a mild soap and water solution,
clean the face of the CRT and the rear surface of the filter.
(The rear surface is the side opposite to that having the tape
attached. It can also be identified as the side exhibiting the
most glare from reflected light.)
Avoid touching the face of the CRT
or
the back of
the filter during the rest of the procedure. Otherwise,
the filter will have to be removed for cleaning.
Set the filter in place in the recess in the neoprene
mounting ring, with the side containing the masking tape
on the outer surface. (The outer surface is the side
exhibiting the least glare from reflected light.) The filter
should fit flatly on all edges. Otherwise, it may break when
tightened in place. When properly installed, the front
surface of the filter should be approximately flush with the
front surface of the frame. If it is not, it may be improperly
seated in the neoprene ring. A toothpick, or other
non-abrasive object may be used to move the lip on the
neoprene ring sufficiently to allow the filter to move past
the lip. If the early version of the frame is installed, a
possible cause of improper seating could be that a corner
clip may be mounted insufficiently far into the corner of
the frame. I n that case, loosen the appropriate corner
screw, push the clip into the corner and retighten.
3-7