Tektronix 2430 - Page 235

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4. If 2 and 3 above are ok, then select a pattern test and check that the data lines are the same
states as the pattern; i.e., 10100101 would have the 07 pin = 1, 06 pin = 0, etc. If ok, replace
U542.
NOTE
First clock pulse is the write to U541, the second is the read from U542.
3. Run test 2220 in CONTINUOUS mode and check U541 pin 11 for clock pulse MOOECON activity.
HI; if not, troubleshoot Power Up circuitry (schematic
2. Check U541 pin 1 for PWRUP
diagram 23).
Now using the CH 2 probe:
1. Set up the test scope as per Step 1 of the 2110 troubleshooting procedure.
If test = FAIL for all test then look for failure using the following steps:
Troubleshooting Procedure:
If run from this level, all four tests are selected in turn. One may execute anyone test by selecting
2221 to 2224. The test involves writing four unique patterns (see test 2200) to U541 and reading them
back from U542. The four patterns test for all stuck-at(s) and for lines shorted to other lines. By know-
ing which test fails and the bit pattern, one may easily determine a bus problem by observing which
bits are the same in the failed tests.
The MOOECON register is two components, latch U541 and read-back butter U542. The test result is
set to PASS, any failure sets it to FAIL.
Testing Method:
Mode Control Register A11U541 and A11U542 (schematic diagram 17):
2220
MOOECON
If ok, repeat steps 2 and 3 for U540, and replace U540 if steps 2 and 3 pass.
NOTE
Must select test mode of RUN ONCE for stability.
4. If 1 and 2 above are ok, then select a pattern test and check that the data lines are the same
states as the pattern; i.e., 10100101 would have the 07 pin = 1, 06 pin = 0, etc.
3. Check U532 pin 19 for clock pulse activity (WR strobe from System /-LP).
2. Run test 2210 in CONTINUOUS Mode and check U532 pin 1 for MISC to be LO during the time
of the trigger strobe. If not, troubleshoot the Register Select circuitry (U550 and U450D) for proper
operation.
Now using the CH 2 probe:
1. Set up the test scope as per Step 1 of the 2110 troubleshooting procedure.
If test = FAIL for all tests, then look for failure using the following steps:
Troubleshooting Procedure:
Table 6-6 (cont)
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