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Maintenance— 2440 Service
Table 6-6 (cont)
NOTE
Since the Front Panel
m
P is being reset in this test, there is no way to HALT if one
chooses a CONTINUOUS loop mode and runs the tests from the front panel. However, to
allow access to these features for any possible troubleshooting, looping has not been dis
abled. ONCE A TEST IS INVOKED IN CONTINUOUS MODE, A POWER OFF/ON CYCLE
MUST BE USED TO EXIT FROM THE FRONT PANEL. Via the GPIB, the tests may be
started and halted by sending the appropriate commands.
S et up the test scope as in Step 1 of the 2110 troubleshooting procedure.
Run tests 4100 through 4600 in C O N TINU O U S mode. Use the CH 2 probe for the following checks
while the specific test is selected and running.
4100 A13U861 pin 9 (FPINT):
1.
Check U862 pin 1 for 0.2
ns
negative strobe during the HI period of the trigger strobe. If not
present, replace U 862.
2.
Check U861 pin 9 for a H I-to-LO transition. If not occurring, replace U 861.
4200 A13U861 pin 6 (FPDNRD):
1.
Check U861 pin 1 for a negative strobe during the HI period of the trigger strobe. If not present,
replace U 862.
2.
Check U861 pin 6 for a LO-to-HI transition from the strobe at U861 pin 1. If occurring, replace
U 861.
4300 A 13U 700 pin 12 (W R TO HOST):
1.
Check that U861 pin 9 has a HI pulse. If not, select 50 ms/div and ENVELOPE acquisition mode
on the test scope; then, run test 4000 for the scope under test. At pin 12 of U 700, check for a
strobe occurring near the falling edge of the trigger strobe. If the strobe is ok, replace U 861. If
missing, test for 4 M H z at U700 pin 5 and replace U 700 if the 4 M H z clock is ok.
if the 4 M Hz clock is missing, troubleshoot the clock source. Restore the prior test scope setup as for
test 2110 (a good use for the AUTO STEP SEQ UENCER).
4400 DIAG BYTE A13U700:
1.
Check that the enable pulse to U751 (pins 1 and 19) is present and save to REF1. If not present,
check for an open between U862A pin 1 and U751 pins 1 and 19.
2.
Display REF1 and probe U751 pin 18, 16, 14, and 12. These should all be LO during the time
U751 is enabled. If not LO, it indicates either a problem in U 700 or an invalid DC voltage level at
one of the U700 inputs. If one of these four diagnostic bits is HI and the supply pins, etc., are ok,
replace U700.
4500 A 13U 700 pin 13 (FPDNRD):
1.
Select the 1/2 TRIG PO SITIO N and set the Sec/Div setting to 1 ms on the test scope. Check for
the FPDNRD clock pulse to U861 at pin 3 (leads the trigger strobe rising edge about 120
(is).
If
missing, replace U700.
6-80
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 ...
Page 433: ...WAVEFORMS FOR DIAGRAM 2 ...
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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 ...
Page 458: ...WAVEFORMS FOR DIAGRAM 12 ...
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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 ...
Page 518: ...2440 Service ...
Page 519: ...FIG 4 L V H V PWR SUPPLY ...
Page 520: ...FIG 5 ACCESSORIES 2440 Service ...
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