Maintenance—2246 1Y and 2246 Mod A Service
TROUBLESHOOTING
INTRODUCTION
Preventive maintenance performed on a regular
basis should reveal most potential problems before
an
instrument
malfunctions.
However,
should
troubleshooting be required, the following infor
mation is provided to aid in locating a fault. In
addition, the material presented in the Theory of
Operation and Diagrams sections of this manual may
be helpful while troubleshooting.
TROUBLESHOOTING AIDS
Diagnostic Firmware
This instrument contains built-in diagnostic routines
that can aid in localizing failures. An automatic
power-up self test checks the system RAM and ROM
and readout interface circuitry. If a failure is
detected, this information is presented in either of
two ways: a flashing code display on the Trigger
LEDs or, if the instrument is capable of presenting a
readout, error messages in the crt display. In
addition to the power-on testing, various diagnostic
routines can be run from the service mode using the
SERVICE MENU. (See Internal Testing Capabilities in
this subsection for the details.)
Schematic Diagrams
Complete schematic diagrams are located on
tabbed foldout pages in the Diagrams section.
Portions of circuitry mounted on each circuit board
are enclosed by heavy black lines. The assembly
number and name(s) of the circuit(s) are shown
near the top or the bottom edge of each diagram.
Functional blocks on schematic diagrams are out
lined with a wide gray line. Components within the
outlined area perform the function designated by the
block label. The Theory of Operation uses these
functional block names when describing circuit
operation as an aid in cross-referencing between
the circuit description and the schematic diagrams.
Component numbers and electrical values of com
ponents in this instrument are shown on the sche
matic diagrams. Refer to the first page of the
Diagrams section for the reference designators and
symbols used to identify components. Important
voltages
and
waveform
reference
numbers
(enclosed in hexagonal-shaped boxes) are also
shown on each diagram. Waveform illustrations are
located adjacent to their respective schematic
diagram.
Circuit Board Illustrations
Circuit board illustrations showing the physical lo
cation of each component are provided for use in
conjunction with each schematic diagram. Each
board illustration is found in the Diagrams section on
the back of a foldout page, preceding the first
related schematic diagram (s).
The locations of waveform test points are marked on
the circuit board illustrations with hexagonal outlined
numbers corresponding to the waveform numbers
on both the schematic diagram and the waveform
illustrations.
Circuit Board Locations
The location of a circuit board within the instrument
is shown on each foldout page along with the circuit
board illustration.
Circuit Board Interconnections
A circuit board interconnection diagram (schematic
Diagram 16) is provided in the Diagrams section to
aid in tracing a signal path or power source between
boards. All wire, plug, and jack numbers are shown
along with their associated wire or pin numbers and
signal names.
Power Distribution
Two
Power
Distribution
diagrams
(schematic
Diagrams 14 and 15) are provided to aid in trouble
shooting power supply problems. These diagrams
show the components that the various voltages are
applied to and the jum per connections and de
coupling components used to apply the power to
those circuits. Excessive loading on a power supply
by a circuit fault may be isolated by disconnecting
the appropriate jumpers.
Grid Coordinate System
Each schematic diagram and circuit board illus
tration has a grid border along its left and top edges.
A table located next to each schematic diagram lists
the grid coordinates of each component shown in
that
diagram.
To
aid
in
physically
locating
6-5
Содержание 2246 1Y
Страница 13: ...2246A Service 7062 01 X The 2246 1Y or 2246 Mod A Portable Oscilloscope ...
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Страница 69: ...Theory of Operation 2246 1Y and 2246 Mod A Service 15 V 6081 07 3 32 Figure 3 4 Simplified Sweep Circuit ...
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Страница 311: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 1 0 V r l III B f e I l i 6555 39 ...
Страница 314: ...15 14 13 12 11 10 9 8 7 6 5 12 11 10 9 8 7 AT117 A TI 271 1 2 3 4 5 6 6555 70 Figure 9 8 Hybrid pin identifiers ...
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Страница 345: ...HORIZ MODE ALT A SEC DIV 2M s B SEC DIV 5 mS HOLDOFF MIN DELAY INTENSIFIED ZONE STARTS MIDSCREEN ...
Страница 347: ...BEV JUNE 1991 7062 18 ...
Страница 349: ...2246 1Y and 2246 Mod A Service WAVEFORMS FOR DIAGRAM 6 6555 43 I ...
Страница 354: ...A L B i C 1 D 1 E i F i G 1 2 3 4 5 6 7 8 2246 1Y AND 2246 MOD A _________A fc A A REV JUNE 1991 7062 19 ...
Страница 355: ...I BOARD LOCATION 8K 8J 8H 7H 8H 8H 7J 8D 7H 8H 8J 8J 7K 8K 10D 6L 6K 6L 6K 6G 5H I ...
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Страница 376: ...SCHEM LOCATION BOARD LOCATION 2E 2B 7F 4B 4J 5D 3J 5C 4L 6D 3L 6C 5L 7D 3L 7D 3M 7D 5M 7D IB 1A 1C 1A 2B 1A 3B 1A ...
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