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I trying to get a 3.5" floppy working with my Ohio Scientific Model 600 (C1P) and 610 replica using the PCB design from Lance Klyball along with his V3 data separator board design. I'm wondering what timing the one shots should be adjusted to for a 1.44MB 3.5" floppy running at a 500 kHz Tx Clock.

I've made the mods on the 610 board for dual sided operation as described in the Dragon Byte manual and strapped the clock to 500 kHz.

There are three adjustments on the 610 board that are documented in the Sams service manual and the Dragon Byte Technical manual:

SAMS Manual (I assume these are for 8" drives):
Tx Clock: adjust R18 for 400nS
Tx Data: adjust R9 for 400nS
Rx Clock: adjust R10 for 1uS
Rx Data: adjust R19 for 6uS

Dragon Byte Manual:
Tx Clock: 5" 350nS, 8" 250nS
Tx Data: 5" 50nS, 8" 250nS
Rx Clock: 5" 1uS, 8": 1uS
Rx data: 5" 6uS, 8" 2.5uS

For the data separator I have read that I should set the one shot to 4 uS for an 8" floppy and 2 uS for 5.25".

What would be suitable values for all of the above for a 3.5" floppy?

Regards,
Jeff

Just an update: The drive is now working (on most tracks, using the program at http://www.pdp8online.com/osi/osi-floppy-test.shtml) in 720 KB "double density" mode with a 250 kbs data rate and the timing for an 8" drive.

What is the V-3 data separator?
Is a new one available?
First I heard of it.
Also what type of three inch floppy drive did you use?
I tried using some with the original Klyball data separator and an eight inch 470 controller card.
It did pass disk test but I could not copy eight inch images to it from the gotek.
I am guessing its the wrong rotation rate, ie 300 vs 360 rpm.
I didn't try it with a five inch controller or five inch image.

Jeff or Others,
I can't seem to find a definitive source for the various pulse width settings for the 610 board for:
3.5", 5.25", 8" drives. I have the Sams 610 manual and set to those, but at this point I don't know if that was for an 8" drive or not.

Do you or anyone have the pulse width settings for the above drives?
What would be the pulse width settings for the Klybal V2 data separator for the above drives?

Jeff, I saw you had something on the Dragon Byte Manual. What is this? I'm not familiar.

Also, I want to get a GoTek working and have had no success either. The diag tests (floppytest_v1.04u) working against the Gotek fails as well.
I was using the timing from the Sams 610 service manual and am now questioning these timing values for the floppytest_v1.04u test code.

Any help would be greatly appreciated.

Andy

in my experience , i have just used the 8 inch timing with a 1.44 as a 8 inch replacement you need to change the track # data in the software .

same goes for 720k, use 5.25 timing change the track data in software