On Thu, 12 Aug 1999, Nicolas Welte wrote: > Aha, I had a look at the schematic for those drives and you probably > mean the input at pin 14 of CN6 or P6. You're right, this input is > somewhat connected to an optional circuit, but this is not related to a > track 0 sensor. As I understand that circuit, it will activate the > spindle motor for some seconds each time it is triggered by a disk > change signal. This disk change signal can either be generated by the > write protect sensor (J3 closed) or by an extra disk change sensor at > pin 14 of CN6 (J4 closed), but I've never seen a drive with that extra > sensor or the optional circuit. Not to mention that J4 is open so that it won't work anyway. > Pin 6 of connector P5 carries the TR0 input to the PA0 input of VIA UC1, > via two inverters of UC6. The signal can be disabled by J3, which > enables a permanent connection to GND. > It does go somewhere, it's visible in the schematics. And it works, a > real 1541B/C drive with J3 open makes use of the sensor and doesn't > rattle the head on a disk format or error anymore. I missed that circuit. So, the 1541B/1541C can use a drive with track 0 sensor. But this does not make the drive electrically incompatible as Commodore claimed. If your drive doesn't have a track 0 sensor, you just close J3. If you use a drive with a track 0 sensor on a board that doesn' support it, it doesn't matter as it isn't connected to anything. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
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