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Re: ST314 drive replacement.

Posted: Sun Oct 06, 2019 5:13 pm
by stephen_usher
OK, moved the Motor-On line over to line 16 on the ribbon cable and now the internal drive stops working.

Re: ST314 drive replacement.

Posted: Sun Oct 06, 2019 5:52 pm
by stephen_usher
I've moved Motor On back to pin 10. Without it connected the drive isn't recognised at all.

From what I can see on the oscilloscope it's acting normally.

When the drive is accessed the activity light comes on, it seeks but the motor isn't running.

There's definitely 12V getting to it and another Atari drive (the old 720K drive originally in the TT) behaves the same way.

There's obviously something missing.

Re: ST314 drive replacement.

Posted: Sun Oct 06, 2019 6:04 pm
by stephen_usher
Could it be possible that I need to wire all the odd-numbered wires to ground in case the motor ground isn't connected? I doubt it as that should be using the power input ground rather than data ground.

Re: ST314 drive replacement.

Posted: Sun Oct 06, 2019 7:07 pm
by stephen_usher
That's interesting... I put a Flashfloppy-ed GoTek on in place of the floppy.

Strangely it thinks it's the internal drive and drive B at the same time (unlike the real floppy drive). You can access it fine as drive B, both reading and writing.

I think the drive access is a bug in Flashfloppy in that it's seeing the Atari drive strobe and thinking that it's selected continuously.

So, if I could get the drive motor to operate I think it will all work. From what I can see the "Motor On" signal is active low. That's what the 'scope's saying anyway.

Re: ST314 drive replacement.

Posted: Sun Oct 06, 2019 7:39 pm
by stephen_usher
OK. I now have the interface working! Swapping both the motor on and drive select lines to the PC version worked... on another floppy drive and the GoTek.

However, the drive sent by Best Electronics and "guaranteed working" can't read floppies. Gah!

I can try stripping the drive from the older of the two STFMs I have in the loft which has a long slot floppy and try that. The machine's developed a memory fault anyway so either needs a rebuild or used for spares.

Re: ST314 drive replacement.

Posted: Mon Oct 07, 2019 7:05 pm
by stephen_usher
I've discovered why the TDK isn't working... the upper head has become unstuck from the mounting frame during transit. I was wondering what was rattling about inside and then saw the head dangling when I took the top off. Well that was an expensive bit of junk... $99 + shipping + duty.

I'm now retro-fitting the red optic onto the Chinon drive from my spare/not working currently STFM. I'm going to have to change the LED as it's green and I need red. I can hoik the LED out of the dead drive for that.

Re: ST314 drive replacement.

Posted: Mon Oct 07, 2019 8:36 pm
by stephen_usher
At last! Having moved the red light channel over to yet another fascia and swapped the green LED with the red one from the dead TDK drive I now have a fully operational and authentic looking SF314 drive. Phew!
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Re: ST314 drive replacement.

Posted: Mon Oct 07, 2019 10:08 pm
by exxos
:bravo:

Not giving up has it rewards :thumbup:

Re: ST314 drive replacement.

Posted: Mon Oct 07, 2019 10:55 pm
by stephen_usher
The result... my original ST system fully renovated and happy! :D
renovated-st.jpg
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Re: ST314 drive replacement.

Posted: Tue Oct 08, 2019 11:18 am
by tzok
Motor ON is common for all floppies, and regardless which one is selected, motor starts in all, this is normal behavior.

In the standard SF314, the DS1 line from Atari STf is connected to the DS0 pin in the drive, so the drive itself has to be set for DRIVE0. In short ST, there are both lines present on FDD connector, and they are crossed in FDD conector of the floppy drive, so first in chain is DS0, and second is DS1, but internally both have to be set as DRIVE0, same is for Gotek (by default it is set as DRIVE1).