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Where does this go? Floppy drive disassembly

M

maferv

Experienced Member
Joined
Jan 5, 2017
Messages
62
Location
Argentina
I recently got this YE Data YD-380. I was trying to make it work with 360K disks. I tried to find documentation about the jumpers but couldn't, except this service manual that was of little help http://electrickery.hosting.philpem.me.uk/comp/divcomp/doc/YE_Data_YD-380_5.25inchHHHDFloppy.pdf

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So I started messing with them, but couldn't get it to work.

I was closing it back, after cleaning it a little, but I found this plastic thing, I don't know where it goes. Can anybody of you please tell me?

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Thank you
 
IIRC, the YD-380 is one of the weird high density floppy drives that will not read double density disks. Pin 2 which normally does the density select isn't connected on the YD-380.

Could you provide the dimensions of the plastic thing? Helps to figure out where it can't go. I would suspect that it is a guide rail for the read write head; if it is, you should see a matching guide on the other side of the read write head. I don't have a YE Data drive to disassemble and confirm that guess. So I could be completely wrong.
 
I just had a look at a YD-380 i have but it's totally different to the drive pictured, I see nothing like the plastic thing on my drive.
 
Don't know what the heck that is--but it doesn't show on the 380 exploded view here. I don't see anything like that on the 380s that I have.
Click to expand...

I just had a look at a YD-380 i have but it's totally different to the drive pictured, I see nothing like the plastic thing on my drive.
Click to expand...

You mean this isn't a YD-380?

Model:

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YD-380C 1711C

Drive and thing size, for reference:

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Some info I can read:

PCB:
PN138 500-01 REV C 1 D

FD884
KUMAGAYA

ICs:

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YE DATA
MB87633
9208 Z37

BA6589K
213 107

LB1656
2B4

M56733APP
215000

JUMPERS:
I can read DS0, which also appears in the maintenance manual. I think it refers to the first pin pair. Then, I think it says M2 and M1 and I can't make out what these jumpers are for.
 

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I just found out.

thing-position.jpg

Now that we know this, you can tell me what are the differences with your YD-380 unit, and if you know, the jumper settings.
 
My YD-380-1710 are even earlier than modem7's, but closely resemble it superficially. PCB is different and has more jumpers and a DIP switch position for each of the terminator lines--and a head-load solenoid. They're also 96 tpi drives. Manufacture date is 1985-08. Black bezel.

The OP's drive looks like a cost-reduced model--sheet metal instead of a cast frame, etc.
 
Got curious. The only information I can find about 380C is at http://zx-pk.ru/threads/10863-podklyuchenie-diskovoda-5-25-ye-data-yd-380c/page2.html a Russian language Sinclair fan forum. It looks to have pictures which if the model is correctly identified might help identify what should be on the drive. If the topic is correctly translated, the thread is about modifying 380C. Automatic translation mangles technical details.
 
As far as I can understand (limited Russian knowledge) one user there managed to get it working as a 720k QD drive, says he tried all possible jumper combinations and then reading the datasheet he modified two cables from the motor flex to get it running at 360 - 300 rpm. It involves the first and second cables, I think he grounded them, not sure. I think it would be harder to make it work as a 360k drive.

Great find krebizfan.

So according to what other users say, this model is the YD-380C, late model (early 1990s) 1,2 MB only (720k capable with this mod).
 
I don't know about your YD380 drive's jumpers, but my drive already runs at 300 RPM with the HD jumper off. So 720K.

But if you're putting the drive on a PC, you're better off leaving it as a 1.2MB. AT- and later BIOSes are set up to double-step the drive when in low density mode.
 
The manual that the OP pointed to shows pin 2 as not in use (PDF page 40). I found a manual for a dual speed YD-380 (the YD-380-1714), and that shows pin 2 as 'LOW SPEED'. So, there can be functional variations in the different revisions of YD-380.

IBM AT (5170)

The IBM AT uses fixed speed drives. A fitted 1.2M drive is always to turn the spindle at 360 RPM. The BIOS in the IBM AT adjusts the controller's data clock rate depending on what is in the drive:

1.2M floppy in 1.2M drive: 500 KB/s
360K floppy in 1.2M drive: 300 KB/s (controller also does double stepping)

On my IBM AT, monitoring pin 8 (Index) of the controller-drive interface, using an oscilloscope, confirmed 360 RPM when reading either 1.2M or 360K floppies (as expected for the AT).

As for pin 2, IBM'S technical document for the controller shows that pin 2 is labelled as 'Reduced Write' and is connected - the controller outputs a signal on it. An oscilloscope shows about 5V when I am reading a 1.2M floppy, and about 0V when I am reading a 360K floppy.

But because the AT's YD-380 spindle speed is always 360 RPM, the YD-380 used in the IBM AT is either:
- Fixed speed, at 360 RPM; or
- Dual speed, but configured to ignore pin 2.
 
There are lots of jumper options available on various drives--some appearing just as silkscreen over pads not populated and utterly undocumented.

I suspect that one can get most YD-380s to behave any way one wants, armed with the knowledge of what the various configurations (documented or undocumented) are. I've got YE drives where pin 2 can be configured as "READY", for example.

One thing you're not going to get away with however, is calling it a 360K (48 tpi) drive in the BIOS and expecting it to handle 360K floppies. Only drives declared as 1.2M in the BIOS can be natively double-stepped to handle 48tpi floppies.
 
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