Maintenance— 2440 Service
Table 6-6
2440 Troubleshooting Procedures
1
INITIAL INDICATIONS
TESTS FOR
1.
LIFE
Are TRIGGER LEDs flashing? If all lights are flashing, suspect Waveform #tP ROM U480 or U490
(diagram 2) or their selects.
2.
Is there activity from GPIB LEDs during turn-on? If the three LEDs above the crt (LOCK, SRQ,
and ADDR) all light then go through a binary counting pattern (test number 2170), the diagnos
tics are working, and the instrument is alive. Go to Procedure 2.
3.
After 30 seconds of turn-on, press MENU OFF and cycle the SLOPE switch. If the + and —
Slope LEDs light alternately, the System
m
P is alive, and the operating system is active. Go to
Procedure 2.
4.
Did the attenuator relays click? If the relays clicked, the power-on self tests vere running.
5.
If any of the signs-of-life occurred, then assume that there is some “life in ihe box" and go to Pro
cedure 2; otherwise, go to Procedure 8.
2
CRT DISPLAY CHECK
1
.
If the menus are normal (can focus, adjust intensity, etc.), then go to Procedure 3.
2.
If there are no displays then go to Procedure 5.
3.
If there is a display, but the display is incorrect (no intensity control, out of focus, etc.), a dot only,
a vertical or horizontal streak, then it is an analog problem. Go to Procedure 6.
4.
If portions of the readout are missing or wrapped over, but the power-on test runs, the front-panel
controls and the EXT DIAG menus may still be useful. Attempt to use the diagnostics to determine
the failed tests. Also, read the binary code of the first failed test that is flashed by the Trigger
LEDS during the power-on sequence. Use that information as a starting point for troubleshooting,
using the steps indicated for the failed test in Procedure 7, "EXTENDED DIAGNOSTICS” . The
most probable cause of a failure of this type is a bus problem or bad 1C on a bus causing a stuck
bit in Display circuitry of the Time Base/Display board (schematic diagrams 16 and 17). The
busses to suspect are the ones connected to the 1C indicated by the failed test.
3
POWER-ON DIAGNOSTICS
1
.
N O T E : T H IS IS N O T S E L E C T A B L E , IT E X E C U T E S A T P O W E R -O N .
If all the power-on tests pass, go to Procedure 4. If not, then go to Procedure 7.
4
OPERATIONAL PROBLEMS (Not detectable by diagnostics)
NO SIGNAL
Phase Clock Array Outputs A10U470 (schematic diagram 11)
ACQUISITIONS
1
.
Check A10U470 (Phase Clock Array) at pins 11, 12, 13, 14 and 15 for output clocks.
2.
If no outputs, the problem is probably U470 or the input circuit to U470 at pins 65 and 67; i.e.,
CR580 or C582.
3.
If the Phase Clock Array is working, the problem is in the Time Base.
6-37
Summary of Contents for 2440
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Page 91: ...Theory of Operation 2440 Service 3 49 Figure 3 5 Simplified CCD architecture ...
Page 120: ...Theory of Operation 2440 Service Figure 3 10 DC Restorer 3 78 ...
Page 130: ...Theory of Operation 2440 Service 3 88 ...
Page 136: ...Theory of Operation 2440 Service Figure 3 15 PWM Regulator and Inverter 3 94 ...
Page 138: ...Theory of Operation 2440 Service Figure 3 16 PWM switching waveforms 3 96 ...
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Page 423: ...2440 Service Figure 9 4b 2440 Block diagram part 2 6330 27 BLOCK DIAGRAM PART 2 ...
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Page 428: ...2440 Service WAVEFORMS FOR DIAGRAM 1 6 2 8 5 3 2 ...
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Page 432: ...2440 Service WAVEFORMS FOR DIAGRAM 2 BUS ISOLATED 6 6 0 3 4 9 ...
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Page 450: ...2440 Service WAVEFORMS FOR DIAGRAM 8 6603 27 ...
Page 455: ...W A V EFO R M S FOR D IAG RAM 11 WAVEFORMS FOR DIAGRAM 11 6603 29 ...
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Page 471: ... C N i u i t e x r 4 j u J l i 1 i 6 28 5 44 WAVEFORMS FOR DIAGRAM 18 ...
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Page 512: ...A12 2440 Service F IG 3 C IR C U IT BOARDS ...
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Page 517: ...10 16 R E V J U L 1993 Replaceable Mechanical Parts ...
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