Potomac Instruments FIM-21 - Maintenance; Battery Replacement Guide; Lamp Replacement Instructions

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SECTION 4. MAINTENANCE
4.1 General
Routine maintenance procedures are e:xplained in this section,
including changing batteries. Since circuit alignment and linearity ad-
justment must be performed at the factory to maintain guaranteed calibra-
tion of the instrwnent, this information is not included in this manual.
4.2 Battery Replacement
l. Place FIM with battery door (on rear) facing up.
2. Turn door fasteners ¼ turn to left (slots vertical); open door.
3. Remove old batteries, prying out center ones first.
4. Install new batteries, starting with the bottom row and left
side. Observe polarity; positive contacts are to the left in
the bottom row, to the right in the top row. Install the two
right-hand batteries last, the bottom one first, using them
to push back the spring-loaded contact board.
5. Close door and turn fasteners¼ turn to right (slots horizontal)
to lock.
4.3 Battery Types
Use Size D.1.5 volt batteries of a:rry type. Alkaline batteries are
desirable only if the lights are used frequently or if the FIM is used when
its internal temperature is about 40° F. Storage of the FIM in a cool place
extends battery life; heat shortens battery life.
Lamp Rep lace ment
(Dial Lamp) Remove FIM from case. (See 4.5 below) Remove socket
from lamp. Rotate lamp until the three projecting tabs on the
side of the retaining clip are accessible.
a. Free the clip by pinching the tabs together with pliers and
slide it off the lamp.
b. Remove the old lamp and slip the new one in pl ace.
c. Ho ld ing the clip open with pliers, slip it in place on the
new lamp.
d. R eplace the socket.
e. Check lamps before installing unit in case as follows:
connect battery connector, switch FUNCTION switch to BATT,
open lid so as to close interlock switch, swi tch LIGHT switch
on, and check that aJJ. lamps are worki.ng.
4-1