Marko Mäkelä wrote: > One thing that could give some trouble-shooting hints is the voltage I > measured from the IEEE-488 connector. When I powered up the disk drive > but left the PET turned off, there were some 1.4 volts between ATN and > GND. After turning on the PET, the voltage rose to some 3.3 volts. > Issuing a floppy command lowered the voltage (as displayed by a digital > multimeter) by a few millivolts for one sample. This indicates that > something is happening on the bus. I should take the computer and the > drive to an oscilloscope some day. What line drivers you used? CMOS, HCT(MOS)? Once I had similar problem with C64 and SFD-1001. The IEEE-488 schematic taken from 64'er magazin. Originally CMOS driver used after 6821, but only with 7406 worked properly. Frank - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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