Tektronix 213 DMM Instruction Manual page 49

AMPLIFIER BOARD REPLACEMENT. Replace the Am-
plifier 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 upon reinsertion of
the board. Also, make sure that all the pins enter
their respective terminal pin sockets.
SEMICONDUCTOR REPLACEMENT. Semiconductors
should not be replaced unless actually defective. If removed
from their sockets during routine maintenance, return them
to their original sockets. Unnecessary replacement of semi-
conductors may affect the calibration of this instrument.
When semiconductors are replaced, check the operation of
the part of the instrument which may be affected.
Replacement semiconductors should be of the original type
or a direct replacement. Lead configuration of the semi-
conductors used in this instrument are shown in the Dia-
grams section. Some plastic case transistors may have lead
configurations which do not agree with those shown here.
If a replacement transistor is made by a different manufac-
turer than the original, check the manufacturer's basing
diagram for correct basing. All transistor sockets in this
instrument are wired for the standard basing as used for
metal-cased transistors. Transistors which have heat radia-
tors or are mounted on the chassis use silicone grease to
increase heat transfer. Replace the silicone grease when
replacing these transistors.
WARNING
I
Silicone grease can cause eye irritation; there-
fore handle it with care and avoid getting in
the eyes. Wash hands thoroughly after use.
An extracting tool should be used to remove the integrated
circuits to prevent damage to the pins. This tool is available
from Tektronix, Inc. as Tektronix Part No. 003-0619-00.
If an extracting tool is not available when removing one of
these integrated circuits, pull slowly and evenly on both
ends of the device. Try to avoid having one end of the in-
tegrated circuit disengage from the socket before the other
which may damage the pins.
FUSE REPLACEMENT. This instrument contains two
fuses, a power line fuse and a current (mA) input protec-
tion fuse.
Replacement of the power line fuse requires removal of
both cabinet halves (removal of the top half for fuse re-
placement necessitates removal of the bottom half for pro-
per placement of the power cord and probe lead during
reassembly).
REV A DEC 1980
Maintenance-213 Service
Replacement of the current (mA) fuse requires removal of
the bottom cabinet half only.
Refer to the Cabinet Replacement instructions for cabinet
removal, and to Figures 4-8 and 4-9 for fuse locations.
PROBE REPLACEMENT. The complete probe assembly
can be replaced as one unit by simply pulling the coaxial-
type end lead connectors apart (see Figure 4-4) after re-
moving the bottom cabinet half.
TOP
FUSE
REAR OF INSTRUMENT
1481-42
Fig. 4-8. Power-line fuse location.
Fig. 4-9. Current (mA) input fuse location.
4-11