5.25" drive jumper settings
#1
Information 
Here is a datasheet with numerous 5.25" drive's jumper settings.

5.25" drive jumper settings
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#2
(08-31-2014, 10:36 AM)admin Wrote: Here is a datasheet with numerous 5.25" drive's jumper settings.

5.25" drive jumper settings

I acquired a Kaypro 4/84 which is equipped with DSDD Epson SD-521 drives.  This is an odd drive with a"push button" mechanism and I can't find documentation for it.  But the reason for writing is that in testing the drives with the SCP I found the following:

The Kaypro floppy cable is not twisted, so A drive is jumpered to DS0 and B to DS1.  Except for this difference both appear to be the same.  A drive reports as D0 to the SCP, shows the maximum track as 42, performs the speed test (approximately 300 RPM) and erases and tests media.  B drive reports as D1 to the SCP, responds to the max track test, does not perform the speed test and reports it can not find the index sync. 

It can't find the sync pulse because the motor does not spin.  When the B drive is connected to 12V power but NOT connected to the SCP via the twisted cable, the motor runs indefinitely.  This is not the case with the A drive.  When drive B is powered with 12V and the twisted cable is connected to the B drive its motor does not run, whether the SCP is powered or not.

In other words, A drive spins but only on command from SCP, while B drive spins only while not under command from SCP.  It behaves this way whether jumper DS0 or DS1 is selected.   There must be some configuration difference but I can't see it and I can't find any docs.  Do you have any suggestions?
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#3
Without jumper information, it's hard to know what is going on. Have you tried each drive independently with the jumpers set identically?
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#4
(09-21-2015, 08:56 AM)admin Wrote: Without jumper information, it's hard to know what is going on.  Have you tried each drive independently with the jumpers set identically?

Yes, alas no soap.
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#5
It could be that the drive electronics have a problem.
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#6
(09-21-2015, 03:00 PM)admin Wrote: It could be that the drive electronics have a problem.

I found another variable: drive jumpering.  A little background:  Recently I had been testing some 5.25 inch Kaypro drives, from Epson and Toshiba, using the SCP as a drive-exerciser and measuring max track and drive speed.  I was puzzled by the fact that the drives would respond to the track test but not the speed test.  What would happen is that after starting the speed test the blue light on the SCP board would flash for a fraction of a second and go out.  The drive motor would not start and the test would not display any speed data.

I tried the same tests with a 3.5-inch Samsung drive attached to the SCP and it completed both successfully, so I eliminated the SCP as the source of the problem.  I looked at the 5.25" jumper settings here and selected the Toshiba, using D2, HM, LD and TM.  The drives had come jumpered to use HD instead of HM; when I made the change the drives responded to the speed test.

From this I concluded that the SCP must be monitoring the motor start signal in order to perform the speed test.  Can you confirm this?

Thanks,

-CH-
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#7
SCP monitors only the index pulse pin during the speed test, clocking the amount time between index pulses and converting that into a physical drive speed. So, I am guessing that is disabled with the jumper in the HD position.
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