atar wrote on 2026-01-12, 19:50:

Trying to restore a Toshiba T1950CT laptop. Bought a replacement belt on German EBay, and it kind of works for a few floppies, b […]
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Trying to restore a Toshiba T1950CT laptop. Bought a replacement belt on German EBay, and it kind of works for a few floppies, but at some point the belt slips of a pulley. It feels like a belt is maybe 1-2 mms too long, but this is unlikely because the guys sell quite a lot of this belts and I see no complaints.

Have cleared the motor and the pulleys multiple times, doesn't seem to help. Actually the old one hasn't have sicked to anything.

After fitting the belt it works really good some minutes, maybe one hour, and then slips off, the drive starts making weird noises and dramatically increasing the read errors rate. Then, after re-fitting it's ok again till it slips off the next time. The cherry on a top is that this drive is really at the bottom of T1950CT, I literally have to disassemble the whole laptop to get to the floppy drive.

So, the questions:
- am I doing something obviously wrong?
- has anyone successfully replaced the belt in Citizen V9DA-71B?
- Can V9DA be replaced with a more reliable maybe even beltless drive? It seems that not all 26 pin drives have the same pinout.

Try oiling the disk spindle and tensioner wheel brass bushings, if that's stiff then it can cause enough extra tension that the belt would pop off. Make sure there is no oil remaining on any part of the belt path as that would stop the belt working.
The belt popping off in use is a common complaint with belts for the Citizen drives, especially on the Compaq LTE Lite's V1DA-15B - same mechanism but different pinout & connectors.

I have found that regular real rubber belts don't seem to work for floppy drives, instead I've been using my own 3d printed TPU belts with quite a good success rate. A rubber belt bounces because of the high tension and I didn't get good speed regulation. I think they require harder and less flexible materials to get the necessary torque to spin the disk
.
Additionally, you might need to oil the stepper motor for the head arm because if that jams up then that also causes the drive to not work. While you're in there, put IPA into the switches for the disk detect, HD detect and WP detect and cycle them a bunch of times to make sure that when the drive is back together it can detect disks properly.

From what I recall, the pinout is standard but you'd need a new floppy cable because the T1950 uses a regular 1mm pitch 26-pin FPC on the mainboard side but 1.25mm on the drive side: https://retrocomputing.stackexchange.com/ques … -a-toshiba-t19x
You could probably get away with installing a direct-drive floppy in its place if you get a generic 26pin 1mm pitch FPC cable and something like a Teac FD05HG. But if you do take that route, verify the power and ground pins before applying power, I do think it's the same pinout from what I recall but I haven't tried it myself because I got the citizen drive working in my T1950CT. I like the Citizen drives more than the Matsushita EME278 drives you'll find in earlier models, the citizen drive is easier to work on, more robust and reliable than the EME27x drives.

Thank you. Oiled it some time ago, will do the rest the next time it happens. I suspect I've got one floppy which causes the problem, for now I simply avoid using it and the rest seems to work.

The drive is not ideally compatible with my USB floppy drives. Don't know, which one to blame. Since I have a working CF card, I've been formatting, writing and reading floppies on the Laptop only. This works good at least with one floppy disk I picked for experiments.