Tektronix 213 DMM Instruction Manual page 43

either cabinet half as it is liften off, it can drop
free and be damaged.
2. Remove the bottom cabinet half and note the position
and routing of the power cord and probe lead (see Figure
4-4) and the PWR (BTRY) LED led (see Figure 4-9). Lift
the instrument out of the top cabinet half and set the cabi-
net halves aside. Be sure the rear panel insulated compart-
ment cover and the cabinet screws have not fallen free to
become I ost.
CABINET REPLACEMENT. Replace the cabinet halves in
tlie reverse order of Removal. When i;etting the instrument
into the top half and when installing the bottom half, be
sure the instrument settles onto the plastic guide posts so
the cabinet fits together completely without being forced.
After setting the instrument into the top half, be sure the
power I ine cord and probe lead are properly routed and
placerl in their respective cabinet exit slots before installing
the bottom half (see Figure 4-4). Install the rear-panel
compartment cover and securing screws.
A
suggested
method for installing the rear panel cover is to install and
lightly tighten the screws, then insert the cover hinge into
its respective hr'es and tighten all the screws.
BATTERY REMOVAL. To remove the batteries, remove
the cabinet, (see Cabinet Removal), set the instrument on
its top, disconnect the battery lead, and remove the battery
,·etainer hold-down screw. Remove the battery retainer and
batteries, then tilt the instrument up on its side nd remove
the other battery retainer.
~
Do not set the batteries on a metal surface as
the bottoms are at a one cell potential diff Prence
and one of the cells will be shorted and destroyed.
Also, the cell tab connected to pins
1
and 3 of
P444
may be long enough to touch the other
tab on the cell which will short out the cell and
destroy it. To prevent this problem, the negative
tab of this cell is folded over ¼ inch and soldered
before leaving the factory. It is recommended
this same procedure be followed
if
other than
a direct replacement battery pack is used.
BATTERY REPLACEMENT. Replace the battery in the
reverse order of Removal. Be careful not to overtighten the
battery retainer hold-down screw.
A/D CONVERTER BOARD REMOVAL. To remove the
A/D Converter Board, remove the cabinet and batteries
(see Cabinet Removal and Battery Removal), then proceed
as follows:
@
Maintenance-213 Service
1. Turn the instrument over on its bottom and remove the
two nuts holding the A/D Converter Board to the Line
Converter Chassis (see Figure 4 -2).
2. Gently remove the A/D Converter Board by I ifting it up
and free of the terminal pins. Remove the electrical contact
(see Figure 4-7) and set it aside for reinstallation.
AID CONVERTER BOARD REPLACEMENT. Replace
the A/D Converter Board in the reverse order of Removal.
Be sure the electrical contact is properly installed (see Figure
4-7). Be careful not to bend the terminal pins on reinsertion
of the board. Also, make sure all the pins enter their re-
spective terminal pin sockets.
CRT REMOVAL. To remove the crt assembly (crt and
shield) complete the Removal steps of all preceding compo-
nents, then proceed as follows:
1. Disconnect the crt base socket and the three-terminal
connector holder just below and to the left of the crt base
socket.
2. Gently pull the crt assembly toward the front of the
instrument and out of the crt retainer ring. If the assembly
is very tight in the ring, gently rock it back and forth while
pulling it out. Do not rotate the assembly in the retainer
ring over about 1 /8 inch as there is a solder spot on the crt
shield which is located within the retainer ring slot. Rotat-
ing the assembly beyond these I imits may loosen the solder
connection or damage the crt retainer ring.
Disassembly. To disassemble the crt assembly, proceed as
follows:
WARNING
I
Use care when handling a crt. Protective clothing
and safety glasses should be worn. A void striking
it with any object which might cause it to crack
or implode. When storing a crt, place it in a
protective carton or set it flat on a smooth surface
with a soft mat under the faceplate edge.
1. Remove the shield-lead terminal connector from the
three-connector terminal connector holder by bending the
top part of the holder away from the connector and remov-
ing the connector from the holder (see Figure 4-10).
2. Gently pull the crt completely out of the crt shield. Re-
move the crt support ring and lay it aside for reassembly.
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