Can you get a picture of the floppy drive? Sound like the cam that pushes down the disk clamp isn't actuating - I fixed something similar on my samsung 5.25" drive with a 3d printed part.

Regarding a manual, this popped up when I looked for pictures but it doesn't seem very instructional. Might be the extent of what there is for configuration however: http://matthieu.benoit.free.fr/FD1157C_Nec.htm

Looking at the picture there, the lock arm on the front should be moving that cam at the end of the rod, which connects to that black plastic thing. That looks like it would then rotate down the metal box on the spring that then holds down the disk clamp.
What happens when you actuate the lock arm on your drive?

Thanks for reply, I will record some videos and make photos for clarity and post them as soon as I can.

Here's the video with putting floppy and locking: https://www.youtube.com/watch?v=GD-d5xYzjZ4

I also noticed that moving that small lock ring on the pin that is put through the arm (and which holds the white circular plastic element that presses down on floppy disk) makes it sometime start spinning much cleaner versus not spinning at all or making noises. But nothing really makes the floppy start spinning - makes me think I'm missing some crucial piece of puzzle on what makes the floppy spin, or maybe something applies pressure on the disk itself preventing it from moving?

Sounds like the locking mechanism isn't going all the way down, in which case not only the disk won't spin properly, but also the heads won't touch the magnetic surface and thus won't read. My guess your issue is mechanical. I'd carefully investigate this aspect and make sure the mechanism is indeed going all the way down. I faced such issue before and it was due to a metal piece bent out and causing friction with the rest of the body. Once straightened back, the upper arm managed to lock on fully.

I dismantled it a bit further to see underneath the arm and I think the problem may be that the white "starry" element that touches the disk and presses it down is not holding in place - it seems to be moving on the bearing itself. See the photos:

So the white element was further down the pin when I disassembled it, and I could drag it back onto the bearing but as soon as it presses down it will move back again like on this movie:
https://www.youtube.com/watch?v=hz3H0bGgzk4

I may be wrong but it does seem like it shouldn't move like that and rather sit tightly on the bearing to engage always with the same force. If it can move up, but not down it would end up in that weird lifted position compared to the position of the whole arm - the arm may be at the right position but the white element won't? Maybe something worn out with time and lost the grip on the bearing though I have no idea how it would be attached to it initially.

The spring underneath the white plastic part should push it up and put the pressure on the disk when you engage the lock.
it seems like that white part unable to move smoothly due to dirt causing friction
you can tried to clean it, drop a small drop of machine oil and made sure it can move back after being pressed.

So I tried to put a washer from the top of the white element as currently the spring rests on the bearing and does not apply pressure on the white thing, which makes it move upwards. Unfortunately this put so much force on the whole thing that now the white element does not move up, but it also barely spins 😒 so it must be something that attaches white element to the bearing itself.

Here's the plastic element flush with the bearing (as I think is intended):

This happens as soon as some force is applied to the white element, for example when it presses against the floppy, it would loosen on the bearing and move upwards:

Here's this but seen from the other side - you can see the bearing now sticks out and means the white element is no longer firmy pressed against the floppy:

Here's my hack attempt that ended up putting too much force onto the bearing so it won't spin easily, but the good thing is - the spring was pressing white element down now and it won't come up. But I think the original solution had the white element somehow attached to the bearing itself - maybe something broke off. Would be great to see how this looks in same model:

nhattu1986 wrote on 2024-08-14, 08:55:

The spring underneath the white plastic part should push it up and put the pressure on the disk when you engage the lock.
it seems like that white part unable to move smoothly due to dirt causing friction
you can tried to clean it, drop a small drop of machine oil and made sure it can move back after being pressed.

Hmm, on the other photos you can see that the spring rests against the bearing only, which means it's not pushing the white element currently (not sure if that was always the case, maybe something broke off there). So my line of thinking right now is that the white element should stick to the bearing more than it does now, because as soon as it pushes against something it slides along the bearing and looses any force that would be applied to the floppy.

Quick iteration on some solution to keep that white thing in place, I wrapped some tape around the bearing to create more friction between it and the white element and now it stays in place. I managed to spin a floppy disk for the first time and I can see the arm now engages nicely and without floppy closes the gap, creating some tension on the spring. But... it still won't read the disk and it may now be a case of jumpers though I followed the instructions, but also I encountered interesting thing:

When I put floppy in reverse (so main side down) it spins it without a problem, when I put it the "normal way" with main side up, it will spin for a second and then stop completely - at this point the motor is turned off and it wont spin again until I unlock, eject and put floppy again. I tested it on two floppies so far and both would spin on that wrong side and not on the right side. This is really weird and it's been 3 decades since I used 5.25 flopps so I may be missing something but can't really see how this is different and why the motor decides to stop.

So some progress on the spinning but not yet there, and there may be still something up with the head and solenoid (not sure it actually engages?)

Hah, that's rubberducking much but I realized that the stop of the motor is expected because I'm not yet reading the disk. I checked by going to drive "A:" and it starts spinning again so that's another step forward, but gives me "General Failure Reading Drive A" now. Guess I will have to check the head a bit more and maybe ensure the jumpers are right..

You probably fixed a side-effect of the real issue. I feel your real issue is not the white claw. It's the arm not pressing down enough. The white claw must be able to turn smoothly without major friction. As I said, even if you make the floppy spin, the heads won't read anything if they're not touching the disk.

To test this theory, have the disk spin, and issue a DIR command on the disk. While it's attempting to read, slightly push down on the read head (do not push hard or you'll ruin the head and the disk too). If reading succeeds, you have confirmed my theory.

For jumpers, I'd leave them alone if nobody touched the drive since it was stored.

noizex wrote on 2024-08-14, 01:56:

2) Move the lock lever which lowers the "spindle" that should (I assume) press on the floppy center and start rotating it - but it doesn't happen. The plastic element that presses downwards on floppy is not tightening it enough for it to start spinning.

It's not very clear from the video, since you've focused mostly on the spindle and not the actual clamping mechanism, but I think you are not locking it all the way. In short, the end of the arm on the lever shaft travels in an opening cut into the clamping metal piece. The way the cut is made there is a sort of bump that you need to get past, this prevents the arm from just working itself back due to vibrations and tension. Going past that bump you should feel a bit more resistance on the lever.
This drive does seem to be in great condition but the tiny rod on the end of the arm is actually a sleeve on a rod, the sleeve can seize and make it difficult to get past the bump I mentioned. In general once the clamping metal piece is fully engaged there should be next to no play in the whole arm, and yet you can easily press down on it some more on the video. That's not right.

BTW these particular drives have an issue. The upper head has a metal shield, still in place on your video. It might (in fact, will, unless someone already glued it back) fall off. The "sponge" that keeps it place simply falls apart and separates. You can use the drive without that upper shield, but make sure it does not get loose and falls into the drive. You'll ruin the floppy, and possibly the drive as well when that happens.
In fact if someone did glue that thing back, but without a spacer of some sort (like the original sponge), the shield might now be too low and resting on the floppy envelope. Which will prevent the head from going down, and the clamping arm in turn as well. You can see the shield already missing on http://matthieu.benoit.free.fr/FD1157C_Nec.htm and there is only what's left of the sponge. But the internal copper shield plate is more than enough to keep the upper head happy.

You probably fixed a side-effect of the real issue. I feel your real issue is not the white claw. It's the arm not pressing down enough. The white claw must be able to turn smoothly without major friction. As I said, even if you make the floppy spin, the heads won't read anything if they're not touching the disk.

Yeah it can spin freely now, but I agree - heads may not be touching but not sure what would be the reason. See the other poster mentioning the shield preventing head from reaching far enough and that could be it maybe?

It's not very clear from the video, since you've focused mostly on the spindle and not the actual clamping mechanism, but I think you are not locking it all the way. In short, the end of the arm on the lever shaft travels in an opening cut into the clamping metal piece. The way the cut is made there is a sort of bump that you need to get past, this prevents the arm from just working itself back due to vibrations and tension. Going past that bump you should feel a bit more resistance on the lever.
This drive does seem to be in great condition but the tiny rod on the end of the arm is actually a sleeve on a rod, the sleeve can seize and make it difficult to get past the bump I mentioned. In general once the clamping metal piece is fully engaged there should be next to no play in the whole arm, and yet you can easily press down on it some more on the video. That's not right.

Yeah that video was from before I fixed the white claw to not back off properly which made it properly press against the bottom metal plate - it now presses firmly and the floppy spins. The drive still won't read anything so next thing I'm going to try is to try some software debugging and see how fast it spins, try to move head etc. to see where the culprit may be. I'll post an update if I manage to find anything useful in this research.

Thanks for the info regarding the shield - I wasn't aware of this. I attempted to remove the shield to see what's beneath it and it came off with a bit of force. Here's how it looked inside:

Some gunk which is probably that disintegrated foam. It looked pretty compacted too - not sure what's the height of original foam but this one was not giving much space between outer and inner shield - maybe it causes the shield to stop head prematurely indeed. I will try reading now and if nothing changes then onwards to the software debugging and checking the signals .

I checked now and I can at least better see the head which may help - also I feel that the head is now engaging through solenoid and I haven't noticed it previously - the head would not lower later, it would only be pushed when locking the floppy and then stay on that height. Now I can see it being pulled downwards when reading and lifted up when not. Still General Drive error so will need to get some debugging in place.

I can't believe someone else is looking at the same drive with the same problems as I'm having, just about two weeks ago, after the drive has been around for 40 years...

So I have this same NEC FD1157C drive that I got from eBay. My end goal is to try to get it to read and write disks that are compatible with my Osbourne 1. If that is not possible I just want to be able to read and write disks, just for fun. I have it hooked up to my ~2003 Windows XP build. Windows reports that there is never a disk in the drive. I can see the drive lighting up, spinning up and trying to read something.

I am having the exact same problems with the drive not being able to spin the magnetic media inside the floppy disk. It does not appear to clamp down with enough force or friction to spin the thing.

It even seems to me like the polished steel on the bottom would need a lot more clamping force to generate enough friction to catch the disk - wouldn't it be better if the clamping mechanism was rubber, or something with a little more friction?

I recorded a video, I'm having the same problems as noizex.

https://www.youtube.com/watch?v=0O3bzN5yonE

OK I took apart the lever arm and I can see the exact same problem with the white start plastic. I concur with all of noizex's findings - it's like we have the exact same drive.

https://youtu.be/JIPeL5NccA8

I am thinking of using some glue or cement to try to fix the plastic against the bearing, or maybe 3d print some cap to put on the bearing to prevent the plastic from sliding down.

I can't remember the exact details of my drives right now but isn't there a small lip on the inside of the plastic part to catch the bearing outer race and not let it slip out? Or pehaps the plastic cracked somewhere? Another possibility is somebody tried to "service" this drive and just flooded the bearing with some light oil. That oil spilled and got between the outer race and the plastic, so now it won't be able to hold it with just the friction. In such case the plastic must be separated from the bearing and all surfaces properly cleaned.

If I were to use glue I'd consider replacing the bearing as well if it's noisy. That being said I've never had to replace one of those yet.

There is currently no clip that prevents the plastic from retracting against the outer race, not on either my device or noisex’s. Ours looks the same. It’s possible a clip existed there but fell off over time.

Lip (or catches), not clip, as in the plastic part protruding enough to stop the bearing from slipping out. IIRC the bearing is supposed to go in and out from the other side, that has some catches that can be bent back to release it. The front side should have something of the sort as well but rigid.

A (metal) clip is a nice repair idea though - the problem is it needs to be of very exact dimensions. The plastic here is nylon I belive, it's not easy to work with once damaged and doesn't really like most glues.