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SF314 floppy drive issue

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fatwizard

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Sep 28, 2012
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Location
Indiana, USA
I have been working with the drive from a SF314 external ST floppy drive. It's an Epson SM140A, double sided DD drive. The issue is it begins to stumble on reading a disk about half way through. I thought it was alignment, but it fails to format a disk in the same fashion. At about halfway in towards the hub, it begins to re-seek. This just gets worse the farther in it gets. It won't finish formatting any disk. It reads disks with the same limitation. At about hhalfway, it begins to re-seek, ending in an error message. I replace the electrolytics on the logic board, and substituted a know good power supply, but that didn't help.

I'm hoping someone has overcome a similar situation and can shed some light on what's going on with the drive.

Thanks
 
Indeed I have cleaned and lubed the relevant parts. I discovered last night that if I format a disk as single sided, it will complete without problems. It would seem that there is something up with the top head.
 
Are you sure that it is a SF-314, or is it a SF-354? The 2nd is single sided only.

Which drive mechanics is there? It could be some drives from Chinon or Epson.
 
It has Epson embossed in the frame casting. There is a number printed on the back that looks like an Epson model number,SMD130A000 -02, but I'm unsure if it is. Google searches on that number are not definitive.
 
I can't get any closer. It's been pulled out onto the workbench, and examined every which way. Looking at it right now, and I realize I have made an error. The SMD130A000 -02 number I cited before is actually the number on the Epson drive from my SF-354. The single sided drive. The double sided Epson drive looks nearly identical to the singe sided model. The number printed the the double sided drive is SMD140A000-#1. Searches with that model number mostly find my posts here on the forum.

As you can see, there are some numbers printed on the bottom, but they don't seem to be model identification.

epson1.jpgepson2.jpgepson3.jpgepson4.jpgepson5.jpg
 
So the drive is Epson SMD 140. That really is double sided drive. SMD 130 is single side. On the photos we can also see the upper (2nd) head. 1st thing you should try is to clean both heads using a qtip and a bit of isopropanol . 2nd what you should check is if the head select signal arrives at the drive.
 
The drive has been thoroughly cleaned including the heads. The rails and stepper have fresh lubrication. I haven't checked for the select signal as that seems to work. The drive will format a disk but fails as it nears the innermost tracks. Then it fails, but it is selecting both heads when it should. If I format a disk as single sided, it finishes the format and works fine with the single sided disk.
 
I ask for the signal, because maybe it writes both logical sides to the same physical side. That would then fail to read. The reason could be that the side select signal does not work. Please check.
 
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