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Maintenance— 2440 Service
Table 6-6 (cont)
NOTE
Q0 through Q3
=
0, and Q4 through Q11 map to DO to D7. i.e., Q7 = D3. By knowing
which test FAILS and the bit pattern, one may easily determine the problem bit(s) (look for
the bit column in the failed tests that are the same).
If 2 or 3 tests fail, then there is a bus problem of some sort that must be examined. If all four tests
FAIL, then the problem can be in several locations.
1.
LDCOUNT might not be strobing the data into U220 and/or U 211.
2.
Flip-flop U414A may not be resetting, or U323 pin 3 might be HI due to a failure.
3.
Address Multiplexers U 221, U 212, and U210 may not be operating properly.
4.
Readout Buffer U240 may be defective.
Troubleshooting Procedure:
Set up the test scope as in Step 1 of the 2110 troubleshooting procedure.
Now using the CH 2 probe:
1.
Run test 2350 in C O N TINUO US mode and verify the LDCOUNT strobe pulse at pin 11 of U 222,
U 220, and U211.
2.
Verify that after LDCOUNT strobe, the outputs of Address Multiplexers U 222, U 220, U211 are
stable and of the correct level for the test selected.
3.
Verify that U323A pin 3 is LO.
4.
Verify the outputs of U 221, U 212, and U 210 are stable and correct after the LDCOUNT strobe to
the previous bus.
5.
Verify the RO chip enable to U 240 pins 1 and 15 is LO. If ok to here, replace U240.
2360
Vertical Buffer U 322 (diagram 16):
U322
Testing Method:
If run from this level, all four tests are selected in turn, or one may execute any one test by selecting
2361 to 2364. The contents of the first four bytes of U 322 have been written and will now be tested
against the values that were thought to be written, any failure to match will cause that test to fail.
U 322 is decoded by reading address 2000h.
Set test result = PASS.
If contents of 2000h not equal to 10100101, then test result = FAIL.
If contents of 2001 h not equal to 01001011, then test result = FAIL.
If contents of 2002h not equal to 10010110, then test result = FAIL.
If contents of 2003h not equal to 00101101, then test result = FAIL.
6-66
Summary of Contents for 2440
Page 4: ......
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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 ...
Page 427: ......
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 ...
Page 463: ...WAVEFORMS FOR DIAGRAM 14 ...
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 ...
Page 476: ...WAVEFORMS FOR DIAGRAM 20 ...
Page 490: ...YES ...
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Page 502: ...2440 Service FIG 1 C A B IN E T ...
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Page 510: ...2440 Service SISSVHO Z Old ...
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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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