Tektronix TEK 2754 Service Vol1 Part2 free download

File name TEK 2754 Service Vol1 Part2.pdf

Maintenance - 275412754P Service Vol. 1 MICROCOMPUTER SYSTEM MAINTENANCE Several maintenance aids are built into the micro- "ROM XX TESTS BAD. PUSH A BUTTON TO CONT." computer system. These operating tests demonstrate correct performance or indicate the location of a prob- "ROM XX MISPLACED. PUSH A BUTTON TO CONT." lem, if any. The switch settings that set up two of these tests "TIMER TESTS BAD. PUSH A BUTTON TO CONT." are described first. These are followed by descriptions Cross-reference tables between the ROM and RAM of the three tests. numbers given in error messages (XX) and the circuit numbers of the parts are given in Table 6-8 and Table In the first test, the microcomputer executes a self- test that verifies, as much as possible, correct opera- 6-9. tion. RAM, ROM, and interface adapters are checked. If the entire test is successful, the instrument initial- Any failure found is indicated by LEDs on the GPlB izes and begins normal operation. board. The second test forces the microcomputer to cycle through all of its addresses. This test requires less of the system to run than does the first test, so it may be used to troubleshoot problems that disable the first test mode. Microcomputer System Test The third test exercises the instrument bus to iso- The microcomputer system test is chosen by setting late problems in data transfer between the microcom- switch 8 of S1050 closed and switch 7 of S1050 open. puter and the instrument. The microcomputer reports the test results via the LEDs on the GPlB board rather than on the CRT, allowing this test to be performed when the display is inoperative. If a problem is found, the test stops and the problem is indicated by one of the LEDs on the GPlB board. If no problem is found, the system test takes two minutes. Memory Board Option Switch The system test does not begin normal operation S1050 on the Memory board selects the microcom- after the test is complete. puter system test modes, as well as selecting some instrument options. Figure 6-26 shows the selections Addresses are specified as hexadecimal numbers in controlled by the individual switches of S1050. this d