SYMPTOM: | POSSIBLE SOLUTION: |
No LED's on power up. |
- Is Power cord plugged into wall outlet correctly?
- Is Power cord plugged into the disk drive correctly?
- Check line fuse.
- Check power switch.
- Check clock on 6502 pin 37.
- Check + 5 and + 12 volt lines.
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Flash code. |
- See power-up diagnostic on page 5.
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Device not present message appears. |
- Check for device number change.
- Check UA2 (7414) and the ATN line on the IEEE.
- Check UB1, UB2, UD2 (MC3446).
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AC ripple in 5 or 12 volt lines. |
- Check power supply filter caps.
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No reset pulse. |
- Check 555 and related components on digital board.
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Motor won't run and head does not move. |
- Check UM3 (6522).
- Check UJ2 (741s00).
- Check + 12 voltage sources.
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One or both drive motors runs continuosly. |
- Check + 12V.
- Check UH3, 6522 and logic gates.
- Check ROMs.
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Loads programs with red error LED flashing. |
- Check drive speed.
- Check stepper motor.
- Check drive alignment.
- Check controller ROM UK3.
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Loading is intermittent. |
- Check ROMs.
- Check drive speed.
- Check drive alignment.
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Does not load when hot. | |
Locks-up when loading. |
- Check IEEE components.
- Check ROMs.
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Message of 'FILE NOT FOUND' is displayed. |
- Clean drive head w/alcohol.
- Check read circuits.
- Check alignment.
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Drive fails to read. |
- Check the 311, 9602, 592's, etc. on analog board.
- Check stepper and drive motors.
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