Local pickup - Arche 386SX laptop

[rubber_jonnie]

@rubber_jonnie

I guess you are jamming the "Ready" signal when you connect pin 34 to pin 2...

(supposing a Ready signal is needed on your laptop...)

So pin 2 on the 34 pin connector (34 is disk change) is also media detect, so I think it's messing up the disk density so if I swap a 720KB for a disk of the same size it detects it, but if I swap to a 1.44MB disk it gets upset.

I have seen somewhere that the Citizen 26 pin connector is different, and given the 26 pin connector info I have says pin 6 should be disk change, in theory it should work connecting pin 34 to pin 2 (On the 34 pin connector) since pin 2 is connected to pin 6, but that seems to be density select, so I think maybe the density and drive change are getting muddled.

I'm going to see if I can find an alternative Citizen 26 pin diagram.

[HigashiJun]

I have seen somewhere that the Citizen 26 pin connector is different, and given the 26 pin connector info I have says pin 6 should be disk change, in theory it should work connecting pin 34 to pin 2 (On the 34 pin connector) since pin 2 is connected to pin 6, but that seems to be density select, so I think maybe the density and drive change are getting muddled.

I've just checked a 26 pin FDD pinout, and as you mentioned, it could also be the issue in your case.

An FDD with as much as possible settings would really help you.

BTW, do you know the model of the original FDD ?

[HigashiJun]

Oh, and I found this:

http://www.martinruss.com/sy99adapter.html

and:

...and we have a winner!

Turns out that there are a bunch of old synthesisers which use 26-pin floppies to load samples, so there are lots of people who are really attached to their hardware who are desperate to use modern drives. You can get adapters for about 20 currency units off ebay, or make your own:

http://www.ebay.co.uk/itm/Yamaha-SY...5 ... 2197898977
http://www.martinruss.com/sy99adapter.html

So I bodged up a cable based on the spec from the second link above above, and it almost, but not quite worked --- the trick is that my Toshiba T3100SX actually uses the READY line in the floppy connector, while the Yamaha doesn't; but modern floppy drives don't actually *produce* a READY line so there was nothing to hook it up to. Luckily I found that my drive has a jumper setting that makes it generate READY on pin 34 instead of DSKCHNG. Setting this made it Just Work. A modern beige floppy drive looks a bit startling in the dark grey T3100SX case but it fits fine and works fine.

Also, a handy tip: rewiring connectors like this is easy; I prised the 26-pin IDC connector off the end of the old ribbon cable, split up the strands of one end of the modern 34-way ribbon cable, and pushed each individual wire onto the connector. Looks a bit tacky and you need to trim any unused strands so that they don't brush against the PCB and short out, but it can be done entirely by hand, doesn't need soldering, and is completely reversible.

Hopefully this is useful to anyone else in the same position --- these 26-pin drives are getting increasingly rare.

It could be a good clue to your problem.

[rubber_jonnie]

Oh, and I found this:

http://www.martinruss.com/sy99adapter.html

It could be a good clue to your problem.

That's interesting, it shows that there is no connection for disk change...

However id does show pin 34 connected to pin 8 of the 26 pin block, I'll have to look into that.

Thanks again :)

[rubber_jonnie]

OK, well that was interesting. I hooked up the old drive and did a tweak of the head zero position and it worked, albeit briefly.

Suggests that the belt is possibly good and spin speed is good but there may be a track zero issue or an alignment issue.

Meh!

Also, pin 34 to 8 didn't work either.

How is it detecting disk changes? The old drive when I got it running briefly just now was detecting disk changes. It's stopped agin though...

[stephen_usher]

I know it's not quite the same type of mechanism, but 3.5" drives like yours have a similar adjustment for the head, so this may help you align the heads?

[PhilC]

OK, well that was interesting. I hooked up the old drive and did a tweak of the head zero position and it worked, albeit briefly.

Suggests that the belt is possibly good and spin speed is good but there may be a track zero issue or an alignment issue.

I found that on a few Mac drives that they needed a careful tweak of the zero position and off they went.

[rubber_jonnie]

I know it's not quite the same type of mechanism, but 3.5" drives like yours have a similar adjustment for the head, so this may help you align the heads?

It does, there is a clamp you can loosen to adjust the stepper for the head (I marked the original position), and it seems to be a hairs breadth from working, which makes it even more annoying having got a directory read from it earlier, but I think I need to re-watch that video (I watched it some months ago), thanks for the reminder :)

[rubber_jonnie]

OK, well that was interesting. I hooked up the old drive and did a tweak of the head zero position and it worked, albeit briefly.

Suggests that the belt is possibly good and spin speed is good but there may be a track zero issue or an alignment issue.

I found that on a few Mac drives that they needed a careful tweak of the zero position and off they went.

Yeah, I don't think it's far off, but what worries me more than track zero is head alignment, as if it's that I think all bets may be off.

[stephen_usher]

It's not that bad. That's what the video is all about, adjusting the head alignment. It's far easier with the stepper motor and helical actuator. Loosen the screws slightly and rotate small amounts until you get the disk to read well, or you can stick an oscilloscope on the controller board if you want to try to optimise the signal.