STFM Floppy disk drive problem

[AtariGirl]

Hi all.

I finally found my old 520 STFM the other day.

I plugged it in but found that the drive made a loud continuous whirring noise. After some investigation, I found that the belt had perished. BTW, it's the long button floppy drive.

I ordered an new belt, fitted it, cleaned the heads with IPA and all was well. It loaded up a disk immediately.

But, after a few disks it just started to no longer read them until (after 5 mins or so) it seemed to give up even trying to read them alltogether. So,
I opened it up again, cleaned the heads again, worked a treat.... but, again after some loading the drive graduaally stopped reading disks again. It simply doesn't even try. I tried re-cleaning the heads but that didn't work either.

When it did load a game, some of the graphics were corrupted and then crashed.

It seems to work from cold but then eventually just stops reading.

Also, the ST hasn't been used in 30 years and I can't remember the drive light coming on (drive whirring) for so long when it's switched on. I seem to remember GEM coming up quite quickly if theres no disk inserted. Can anyone tell me if this is correct or is that something to do with the faulty drive?

Can anyone tell me how I can get this drive to work properly again?

Many thanks

PS. I also posted this on another atari forum but this was recommended to me. Hope that's okay.

[exxos]

Which ST exactly do you have ? STM / STF / STFM / STE ?

The first point of call is normally the power supply needs servicing.

GEM takes about 45 seconds to appear without a floppy in the drive.

Also be careful with IPA, in the make sure your heads are totally dry before inserting a disc, otherwise you will literally strip the magnetic media off the disc.

[AtariGirl]

Sorry, it's an 520 STFM. Basic early model.

Understood. That will need looking at for sure. Any idea what the problem is with the drive?

[exxos]

Any idea what the problem is with the drive?

Either it has simply gone bad and replacing it is probably the easiest solution.

But also It can be a symptom of a failing power supply. Because when the floppy motor turns on, the power can drop and cause the machine to crash for example.

You statement of "works from cold" Is also a trait the power supply is failing.

There is a lot of information about power supplies here https://exxosforum.co.uk/atari/last/psu/index.htm

[AtariGirl]

Thanks.

Ah, could be that then. I'll have a look around for a replacement PSU.

It's not crashing in GEM... for example, I was looking theough some disks in GEM and they worked fine until the 4th or 5th disk where it started to come up with the old 'plug in disk drive / corrupt disk' (Cancel/Retry) error. Once it started to do that there was no movement of the head but the disk keeps spinning. Going back to the disks that originally worked, it doesn't even try. Just spins.

Would you know where I can get a long button replacement drive?

[stephen_usher]

The other issue may be that the floppy disks themselves are degrading and leaving their surface coatings on the heads if it degrades the more disks you read.

[AtariGirl]

Yeah, I thought of that. But once the drive stops reading the disks, re-cleaning the heads makes no difference, sadly.

[rubber_jonnie]

I personally haven't had any experience with this, but it could possibly be bad caps on the FDD. I'm not saying it is 100%, but I have read elsewhere replacing them can help.

I would however resolve any PSU issues you may have before pulling the FDD apart again.

[AtariGirl]

Thanks guys.

I'll certainly look into the power supply but I guess I have to assume the drive also has a fault.

I'm a little confused why the drive spins for a long time before GEM appears. I've been told it should only be 10 seconds before GEM appears.

Does anyone know where I can source a working long-button drive? Or anyone who can service this one maybe?

[exxos]

Does anyone know where I can source a working long-button drive? Or anyone who can service this one maybe?

I'm not aware of any serviced drives for sale or anyone who services them any more. Generally the long button ones also tend to be single sided drives. Not sure if yours is or not ?

Generally it is better to have two machines so you can swap things about.

Probably obtaining a MPF920 and modding it for the Atari is a better idea, or as previously suggested, a gotek drive emulator.