Atari STFM 720Kb drive not working

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Atari STFM 720Kb drive not working

Postby jvidia » Sat May 12, 2012 11:56 am

Hello folks.

My original Atari 1040 STFM DD 720Kb drive, stoped reading floppys.

I've used a floppy disk drive cleannig kit but it only worked a few times and is not working again.

The heads try to read the floppy and I only get the normal "crhum crhum" sound.

Tried with 2 diferent DD floppy's that format well on my PC with no errors.
I even managed to format them in this drive after cleanning it. But no more.

This drive doesn't have any belt, right? at leat I don't see any.

What can be done or is this drive helpless?? :(
I'd love to keep this as it is an original one, and no one is selling this kind of drives.
I don't like the ones adapted from PC. :evil:



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Re: Atari STFM 720Kb drive not working

Postby JonB » Sat May 12, 2012 8:57 pm

That is the rather rare "big button" drive. Be very hard finding a replacement. No belt, the main motor is run by a ring of electromagnets under that big disc of metal on the underside. Does the disc spin when the drive starts up? The Sankyo motor looks like a stepper for the head carriage.

I have a small button drive that has the same problem. It cannot find Track 0, although you can see it moving the head and trying, so I think like yours the head movement is OK. One thing to try is to demagnetise the heads. There are various ways to do it - the best is with a tape head demagnetiser, which is just an electromagnet with a probe on the end, connected to the mains (AC). The moving magnetic field is concentrated at the tip, and it is this that removes any residual magnetism from the head. You just need to hold it on the head for a while.

Let us know how you get on.
Too many retro computers here: 1040STfm, Mega4, Ultrasatanx2 , Amiga A500, A500+ and A1200, Acorn Atom x2, BBC Micro, Electron, Spectrum 48k x2, +48, +128k, QL, Oric Atmos, ZX81, Memotech MTX512, Amstrad 6128 x2..

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Captain Atari
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Re: Atari STFM 720Kb drive not working

Postby Nikolas » Sun May 13, 2012 6:03 am

Pc drives are not bad at all, can work as original.
In most cases you need to brake away atari stfm plastic cower some plastic away so then can floppy button to eyect can be usable..
If you guys expirience hardware problems.
1. Always remove chips if possible before soldering.
2. Resolder your hardware, check cables too.
3. If problem continue THEN must be faulty software.

I got 2 Atari ST
Main is stfm, with blitter, with 4 meg of ram, with 16mhz cpu + s-video and audio input to videobox, vdi out
My english may not be correct

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