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Mega STE and Floppy Drive Question


vizfizz
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In addition to the two orphans I picked up yesterday, I'm also in possession of a Mega STE that isn't quite functioning yet either. Seems that we have another floppy drive situation.


I've checked the motherboard of the MSTE and it has the right AJAX and PAL chips for 1.44mb support. Plus the "7" dip switch is in the "on" position. So it should be ready for 1.44mb drive. However, the machine does not recognize the floppy. After several minutes it will get to the desktop...which is good...but it says that drive "A" is not responding. Power light is on for the floppy but no drive access. However I do have drive icons.


This machine was another rescue and I'm beginning to think it was "stripped" of a number of parts before it was sold. (Sometimes people on Ebay and Craigslist can be so dishonest). So after seeing that the motherboard was set for 1.44, I decided to check the floppy itself. Its an Epson. SMD-380-101-05 to be exact... and from what I can tell its a 720k drive.


If a MSTE motherboard is configured for 1.44mb floppies, but someone swapped it out and shoved a 720k drive in there... could this be the reason why the drive isn't responding? Or will the MSTE not worry about the drive and work with it anyway despite its motherboard settings and the drive being a lower capacity drive? I can tell you that the jumpers on the 720k drive are not the same as 1.44. Of course it could just be that the drive is dead.


Otherwise the machine seems to be working. All resolutions work. Blitter present.... so lots of potential!


Thoughts?


Thanks again.

Edited by vizfizz
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Mega STE will set proper mode for floppy depending from inserted disk, better said according to HD tab position. Since no such sensor in DD drives, in your case it will be in DD mode always. But you can try with setting DIP to off pos. Considering possible drive swapping: I don't think that someone needs so eagerly some old, Atari compatible HD floppy drive. Because all drives can be made Atari compatible - and main problem is not the jumpers, but disk change detection - http://atari.8bitchip.info/flomodam.html

I bought used Mega STE some years ago. Drive was DD, and I'm sure that it is factory drive. It was in mint condition, with working original hard drive. Only without keyboard.

Cleaning drive, especially it's heads is first thing you should do. Little pure alcohol ...

Edited by ParanoidLittleMan
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I will check the link. I might be getting over my head technically. I don't want to damage anything. :(.

 

I can try cleaning the heads but I don't think it's that either. The MSTE doesn't even recognize that the drive exists. After several minutes it gives me an error that the drive isn't responding with or without a disk inserted. However I do get drive icons. Weird.

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In case of not recognized drive (and no bootable hard disk present) you will get 4 bombs after 30 secs. Check it if you don"t believe me. How ? - detach floppy cable.

Only weird thing is that you asking for help (on at least 2 forums) and then coming with "I don't think ..". There is people dealing with this over 30 years.

And I add something more, because I;m good guy: Not responding is not same as exists.not . + you have other ST(E), so why not trying other drive.

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I very much appreciate your help!

 

I have disconnected the the floppy cable and turned on the MSTE. There is no hard disk present. Result...No bombs. I actually get a desktop but with no floppy drive icons present.

 

I almost tried connecting the floppy drive from the Mega St to the MSTE but hesitated because I knew it was a 720 k drive too. Different model though.

 

Yes... I do have my 1040 STE to try swapping floppies with. I guess I wanted to try all other things first because this machine is perfect and I didn't want to subject it to any disassembly. It's never been taken apart or opened. All my other machines are rather beat up by comparison. They're all handed down from multiple previous owners.

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Ok. I followed your advice and did some drive swapping. First I took the SMD 380 out of the Mega STE and put it into a 1040STf. The drive worked perfectly. I then took a different (and working) 720k drive out of a 1040STf and put it into the MSTE. The Mega STE failed to recognize or sense the drive. I got the same problem with the original drive that came with the system.

 

I would have taken the drive out of my 1040STE but it too was 720k so, I figured the 1040STf's 720k drive was an adequate test subject.

 

So ultimately... this suggests there's still something wrong with this MegaSTe's ability to detect a floppy drive. When I turn on the machine, the drive lights up, but doesn't spin. I must wait 2 to 3 minutes before I get a "Drive is not responding" error and I must cancel 3 times before it goes to the desktop. I get drive icons, but clicking on them produces the same "drive is not responding" error.

 

I tried switching dip switch 7 to "off" and "on". Neither setting worked.

 

I also checked my chips and here's what versions they are:

 

The Pal Chip located at UA2: C301901-002 MYF

The Ajax Chip: C302096-001A

 

Suggestions?

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If floppy does not spin - of course you need to have floppy inserted for that - then motor on signal activates not. So, check first connector - it's worth to remove cable and put back couple times to clean from rust. What stays for square socketed chips too. Cable can be broken too, although that's unlikely, unless user was some maniac :grin: Voltmeter is big help here too - if motor on line goes not low while LED on drive lights then error is in floppy controller chip or U406, most likely.

And you can try with WD1772 (or like, depending from manufacturer) chip from some ST(E) - it is same, just not designed for HD floppies, and you have no HD drive so far. Only problem may be that chips are soldered directly in motherboard.

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I checked the floppy drive cable with a meter....every connection. The ribbon cable is good. I've reseated the ajax chip...no effect. I've placed a disk in the drive during boot....no luck. The exact same drive works flawlessly in a different computer. I've also removed and reinserted the cable multiple times. If there's rust...I can't detect any.

 

At this point... I feel the UA2 or the Ajax is faulty. Best Electronics sells a new Ajax for $30.00. Perhaps its worth the investment. Would it be worth trying a logic probe on either of those two chips?

Edited by vizfizz
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Progress!

 

I was able to get my hands on an SMD-300 1.44mb floppy drive. I flipped dip switch 7 back "on" and plugged in the drive. Success! High Density recognized. It seems that my MSTE doesn't like any sort of DD 720k drive flavors. I guess once you have the Ajax and Pal that permit High Density sensing, going backwards to DD doesn't work.

 

Thank you!

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