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@bill,
You can just jumper 14/15 to pull motor low
My mpi drives and shugart drives are just on at power up ,the new drives im using require the line pulled low, you can use a inverter or just ground

You will need the inverter if you are going to go to 2 sided drives anyway

Both ways work fine

Ok, here is the mod for dual 2 sided drives. The data separator unmodified, is set to run dual one sided drives with no modifications to it or the OSI controller. For dual 2 sided drives we need to add a hex inverter in ic 3. and modify the D-13 and 610 or whichever OSI controller you are using. Tes...

Don't forget to add the +5 to pin 14 on the 610 ,why they left it out hmm

@Jeff, Yes the 4 change is for sectors, I agree if your system is originally set for 5.25 drives, using a 720k floppy would be ideal, most 1.44 drive need the drive select changed from ds1 to ds0 and thats usually on the circuit board, plus the ready signal needs to be changed to pin 34 , then you w...

I changed my boot file here

26CA = 77
2769 = 76
2779 = 76
27ED = 0E

then you could load up 8" images you could also increase to 80 79 79 in you wanted the extra couple tracks
I have had success with the 1.44 drive writing 13 sectors working solid

Hi Jeff, I want one of those cool drives, The mpi drives cover 40 tracks over the whole drive and the new drive covers 80 but is only going half way right now till you change the os, there might be away to get it to double step but those old drives are flakey at best, so your better off doing new di...

I can confirm the 2 sided drive mod for the 610 with the d-13 floppy.JPG also the white jumper on the d-13 could be placed on the 50 pin header pin 26/28 instead of soldering it to the 34 pin header , I believe this would only be for using 2 double sided drives otherwise can be left off. data%2520se...

Bill good eye , from the pin out above it show drive pin 10 and 12 joined so my image is wrong not pin 8 and 12.I can't see this a a good idea for newer drive maybe ok for jumper selectable older drives I would leave it out I will correct the drawing check the 610 schematic it has the jumper setting...

I guess it really depends what type of drives are being used, for 2 sided 8 inch you would need to jump from 18 to pin 14 of 50 pin connector , the cut would be fine where it is. i think being set up for 2 sided drives would be the most practical, the way it is the side select is used like a drive s...

Here is a modification to use 2 sided drives, my original design is based on connecting a 610 to single sided drives with the side select for drive 2 this mod with make the board more versatile original pinout OSI-610 J3 // Pin Function // FDD Connector Pin 1 // Head Load // 2 3 // Select Drive 1 //...