ddd-f35 extern floppy disk drive questions

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Dbug
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ddd-f35 extern floppy disk drive questions

Post by Dbug »

I recently got hold of a an external floppy disk drive, apparently from germany, labelled ddd-f35 on the bottom.

It has two switches on the back, a power connector and a standard ST external floppy cable, but it did not come with a power brick, the seller told me that it got power from the Atari itself, and it did not have any screw either...

Inside there seem to be a TEAC-FD-235HF drive.

So I tried it, and can't seem to get any reaction from the device, it definitely does not seem to be detected by the MegaSTe.

Does anyone knows these drives, do they actually work from the main machine power (and if not, do you know the polarity/voltage required), and more importantly, does anyone know what the two switches are for?

Here are a few photos:

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image_2021-10-28_161815.png (762.34 KiB) Viewed 1937 times
image_2021-10-28_161846.png
image_2021-10-28_161846.png (1.27 MiB) Viewed 1937 times
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Re: ddd-f35 extern floppy disk drive questions

Post by exxos »

Does the regulator have power input and output ?

It also should be bolted down somewhere .. They run hot and die otherwise.
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Re: ddd-f35 extern floppy disk drive questions

Post by Dbug »

exxos wrote: Thu Oct 28, 2021 3:21 pm Does the regulator have power input and output ?

It also should be bolted down somewhere .. They run hot and die otherwise.
I get 1.97v on the pin 1 and 2.48v on the pin 2
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Re: ddd-f35 extern floppy disk drive questions

Post by exxos »

Do you have your negative probe actually on the tab / case probing the left and the right pin ?

You should have something like 12V on one side and 5V on the other.
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DoG
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Re: ddd-f35 extern floppy disk drive questions

Post by DoG »

What do you connect at the barrel plug? Should be something like 9-35V. Center pin positive.
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Re: ddd-f35 extern floppy disk drive questions

Post by Dbug »

exxos wrote: Thu Oct 28, 2021 3:33 pm Do you have your negative probe actually on the tab / case probing the left and the right pin ?

You should have something like 12V on one side and 5V on the other.
I had the negative probe on the center pin and measured the left and right one with the positive probe.

I actually get 5V if I put the negative probe on the floppy disk metal shielding and the positive probe on the red wire that connects the floppy disk IDC connector to the rocker switch.

The double switch puzzles me.
DoG wrote: Thu Oct 28, 2021 3:38 pm What do you connect at the barrel plug? Should be something like 9-35V
I had nothing connected on the plug, wanted to check the statement of the seller who said he did not require anything, and since I did not know which polarity/voltage, I'd rather ask first :D
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Re: ddd-f35 extern floppy disk drive questions

Post by DoG »

Center pin seems to be positive. The regulator can take up to 35V and it has a 2V dropout and output is 5V so 7-35V in.

Both switches seems to be for power. Right one, seen from back, closest to the FDD cable. If it is ON the barrel jack is used (left OFF). If left one is ON (and right OFF) then power is taken from FDD cable somehow.
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Re: ddd-f35 extern floppy disk drive questions

Post by rubber_jonnie »

I have a Datel unit with a 'similar' 7805 setup and feed it 9-12v for power. The 14 pin plug has no power on it, just control and data signals.

I'd also check for disk ID, it should be DS0.

According to the pinout for the 34 pin connector, pin 7 is what appears to be connected to that switch, but I don't believe it is used, so not connected. 1,3 & 5 are marked as 5v though.

Bit odd overall.
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Re: ddd-f35 extern floppy disk drive questions

Post by Dbug »

Ok, I tried with a 9V center positive, and the disk unit works properly as a B: drive.

image_2021-10-28_182227.png
image_2021-10-28_182227.png (863.96 KiB) Viewed 1904 times

Thanks \o/

So now, what I'm wondering:
- Could I just remove the drive and put a gotek inside
- What would be the easiest/cleanest way to modify a Mega STe to invert A and B so I could put on the external drive?

(Basically I want to be able to boot on the gotek for practical reasons, but still be able to run real software from disk if needed, and I would rather avoid modifying the outside of the Mega STe)
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