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APPENDIX C:
User Access
The
first part of this Appendix describes how to access those parts of OPTIMOD-
TV ordinarily involved in setup, adjustment, or alignment.
The
second
part
of
the
Appendix
provides
information
on
the
disassembly
techniques necessary to access the balance of the circuitry.
1: ROUTINE
a)
User Adjustments: To access the user adjustments, open the small access door
ACCESS
using the key furnished. This will reveal all user- adjustable controls.
b)
Line
Fuse, Power Switch,
and Line Voltage Selector:
These
are
accessed
by
swinging
down
the
entire
front
panel,
which
is
hinged
at
the
bottom.
To
avoid
damage,
this
should
be
done
only
with
the
small
access
door
locked.
Using
the
5/64" hex wrench supplied, remove the three hex- socket screws at the top of the
front panel and carefully swing the panel out and down.
c)
Circuit
Cards:
First,
swing
the
front
panel
down (see
b).
You
must
then
remove
the subpanel by first loosening four DZUS fasteners by turning each one-
quarter turn counterclockwise with a long 3/16" or 1/4" slotted- blade screwdriver.
Taking
care not to stress the flat cable beneath it, tilt the top of the subpanel
outward
and leftward to clear the upper chassis lip and the door support bail at
the right. The PC cards may now be removed from their slots.
****
This procedure is directly reversible with cautions:
--
The
subpanel
should
always
be
replaced
to
protect
the
cards
from
RFI.
-
DZUS
fasteners turn only 1/4- turn. Don't force them, lest they be damaged
in a way that is very time-consuming to repair.
2: SERVICE
General Cautions: These apply to all the procedures described below.
ACCESS
--
For
best RFI protection, replace all screws and tighten normally to achieve
firm contact.
--
If
screws
are
lost,
replace
them
with
screws
of
the
same
length,
since
longer
screws may cause mechanical
interference or internal short circuits.
Most
screws
used
in
OPTIMOD-TV
are
binding
head
to
achieve
secure
fastening
without
lookwashers.
If
a pan
head
screw
is
substituted,
use
an
internal star lockwasher to retain this security.
--
Plating
on
all
screws
is
Cadmium
type
II.
Almost
any
other
plating
is
acceptable unless corrosive atmosphere is present.
a) Cover Removal: Removing the top or
bottom
covers is tedious because thirty
screws must be removed. ( The large number of screws is necessary to achieve an
RF - tight
seal.)
Luckily,
most
service
access
can
be
achieved
without
removing
either
cover!
Specific
instructions
for
doing
this
are
found
further
below.
If you wish to remove either cover, simply remove all thirty screws.
C-1
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