gex85 wrote on 2022-01-10, 12:00:
I have been experimenting with some newer and freshly formatted (in a different PC) disks today, but still without success. The […]
Thermalwrong wrote on 2022-01-09, 00:37:
Since the floppy drive is so important in these somewhat older computers, make sure to exercise it! A fast/ slow / too-tight bel […]
gex85 wrote on 2022-01-07, 16:32:
I replaced a floppy drive belt in the Panasonic CF-150B (aka Tandy 1100 FD) that I was given for free the other day.
It wasn't a real success yet, since the "DIR" command results in errors pretty often and trying to open any file on the disk always gives read errors only.
Since the floppy drive is so important in these somewhat older computers, make sure to exercise it! A fast/ slow / too-tight belt is usually tolerated quite well by old floppy drives - they've got sensors to tell where things are. As long as the drive motor isn't just freewheeling it should be okay.
I've been trying to get a 5.25" floppy drive working the last few days. Had to design up and 3d print a replacement for the arm that hold the disk clamp in place.
I had a bunch of 5.25" disks that are 2HD but were old enough that the formatting was no good (this drive is calibrated and can read 360KB disks just fine). I just kept formatting until it got it right (I was kinda drunk at the time, but I was going the right way). Now with a little bit of oil on the head's motor's worm gear, the drive is able to read and format disks quite reliably 😀
I have been experimenting with some newer and freshly formatted (in a different PC) disks today, but still without success. The drive would just give various read errors all the time.
What makes it complicated is that the drive has a proprietary 24-pin connector and a flat-flex cable. So I can neither hook it up to a different machine for diagnostics and alignment, nor can I swap in a replacement drive or GoTek without wiring up an adapter (pinout is known and documented, but I don't have the necessary FFC/FPC connectors at hand).
I have no experience fixing this sort of problem with floppy drives either, so I'll probably put the whole thing aside for now and decide what to do with it later. Options are probably:
- Try to get the original drive fixed
- Build the adapter and throw in a replacement drive or GoTek emulator (would need to cut the enclosure for that)
- Sell it as-is and let someone else have the fun
You've replaced the belt, but can the stepper / worm gear turn freely? If it's giving DIR then I Guess it's spinning and can read, but maybe it can't move the heads well? Letting some PTFE lubricant soak into the bronze bushings for the stepper motor / worm gear can help. Also sometimes when I jostle the worm gear around, it can fall out of its bronze bushing and get jammed, so slotting that back into place can help. But that would usually be obvious from the sound.
If the drive can seek okay, open a file at the end of the disk a couple of times to see if the head moves freely, if the disk's tracking is off then I've found read errors can happen.
Having had a think about your situation, since the floppy drive is a non-standard laptop type and the laptop doesn't have a hard drive? Then yeah, that's quite a catch-22. I would look at soldering up the adapter to put a regular floppy drive in there honestly. It's not too tough to do with some enamel wire, you can scrape back the FPC to get to the wires and solder onto those if the pitch is over 1mm.
This isn't of much help to you I guess, but I was previously trying to do alignment of one of my 5.25" drives, by doing reads / formats of known good disks, it's tough. I had messed up the track-0 alignment on my Teac FD-55GFR by not realising the drive's main PCB had that sensor and was factory aligned. Somehow I did eventually get the alignment 'good-enough', but it was just guess work and lots of trial and error. I wasn't sure if the drive really worked properly.
Then as I mentioned the other day, I got a working 1.2MB 5.25" drive with its factory calibration intact. This Samsung SFD-560D needed the broken disk clamp cam replaced with a 3d printed one before I could use it 😀
I was able to compare results using IMD / ImageDisk's alignment tool. Imagedisk can step the head over all tracks and you can see in realtime how good the read quality is from each location. This video covers how to use the tool really well: https://youtu.be/VZ9xhFkHZ5c?t=525
It's really impressive, I was able to check that the disk formatted on the Samsung could be read on the Teac and vice versa, across all the tracks. Which means I can now read things like the 5.25" cover disks / games, and the two drives can read files moved from one drive to the other, all the way across the disk.
If there was a way that you could run Imagedisk on that drive / laptop, you could check whether it can step to each track and whether it can read well at each of those tracks. If the drive was disassembled, in some cases the track 0 sensor / motor position could've got out of calibration, so it'd need to be re-done. It's less tough to get right than I initially thought.
I've got a total of 4x 5.25" drives and they've caused me a great deal of frustration, since I only buy the ones sold 'for parts' rather than tested.
2x are very similar Toshiba drives - the ND-08DE-A (FDD6782) and ND-08DEG-A (FDD6784). One has a problem with the bottom head, the other didn't seem to have a working upper head. I had inadvertently ruined the track 0 alignment on both. It took using the IMD alignment tool to really work out what was going on, since it can switch the head it's reading from as well as move tracks.
So I transplanted the less damaged front panel & the top head across onto the newer of the two drives. It didn't take more than a couple of hours to get the bottom head, then the top head properly aligned so that it could read across all 80 tracks. This isn't perfect since this wasn't an alignment disk, just a known good 5.25" DS/HD disk formatted on the known-good drive. But it does work!
Something else I did on the Toshiba drives was replace the electrolytic capacitors, they'd leaked and corroded nearby traces. I think any drives over 25 years old may have bad electrolytic capacitors and are worth checking.
So now I've got 3x working drives - they need installing in PCs, I didn't really intend to have so many but sometimes that's what it takes to get things working. I'm really happy that they're not just decorative any more 😀