Reading online and talking to the indy Radio Shack folks, I'm told I can probably get away with using a rubber band as a temporary replacement belt. I'm sure I can, and now that I know how to dig the floppy drive out, it's something that I could try, but the fewer times I disassemble the laptop all the way from the top shell down to the bottom, the better.

Also, things are starting to look up regarding the mere existence of replacement floppy drive belts.

I just found the strangest advice: Boil the belt in water for about 10 minutes. I have no idea if it'll work, and the one who suggested it never elaborated.

http://www.vcfed.org/forum/showthread.php?47700-T4600C-laptop-floppy-drive-repair

Well, I have a drive of unknown condition with the belt out, a drive that was known working 17 years ago save for a belt now gone slack (but not removed), and an unknown-condition drive on the way. Worst that happens is a belt I already measured breaks apart from really bad advice.

Holy crap, boiling the belt for 10 minutes almost worked! I had a tiny bit of trouble getting the belt back around the disk spindle & guide pulley, but it wasn't quite as much trouble as it should've been. It's just barely too slack for the motor spindle to grip while a disk is in the drive.

I gave the belt another 10 minutes in a bath of boiling water, and it's just not going to shrink any more. It's done.

I got the other floppy drive, and the belt actually broke at the motor spindle. I guess I did too much "come on please just work" last time I used it. I taped it back together, but only so I can size possible replacements; there's no way it'll ever work again in any belt-driven system, let alone an older floppy drive.

BTW, both are Matsushita EME-278TY drives, which Toshiba used in the T4500, T4600, T4700, & T4800 series of laptops.

The third drive came in, & it has the same bad belt problem. My last hope for a local source was a belt from a bargain bin, but it's both too big (218 mm) & too thick.

I have 3 Matsushita EME-278TY floppy disk drives, & all 3 have stretched or broken belts. I've never even *seen* a belt-driven 3.5" drive before this month.

Would anyone happen to have 3 thin spindle belts about 214-216 mm in circumference, 1-2 mm wide, and less than 1 mm thick, you could part with?

I may have underestimated the pre-stretch circumference. I found someone who sells Matsushita FDD belts, giving the circumference as 18 cm, & for about $12 all told. Not bad if it's right, & I'll find out in just a few days.

But if that's right, then the 25 year old belt stretched out another 5 cm in the drive. That's a fantastic amount, but since I pulled them out so easily that they almost fell out on their own, it's also plausible.

The new 180 mm belt came in, and wrapping it around the floppy drive spindles & pulley felt exactly as hard as it needs to be.

Now the motor didn't turn. :/

I hope it's because the motor ribbon missed the PCB connector when I reassembled the floppy drive...

Nope. The motor just isn't turning the belt, but it isn't free-spinning either.

The new floppy drive belt is too wide. Everything else is perfect, but it's too wide to sit right in all three channels.

In good news, the seller I got the replacement from has better communication than most businesses. They want me to send both belts (new & bad) to make sure I get the right-width one.

I got the belt back, but they sanded the new belt down to the correct width instead of replacing it. Eh, whatever works.

I installed it in one of my bad-belt floppy drives, and it's actually grabbing the spindle enough to grab the metal hub & spin the mylar disc! Progress!

But the drive isn't reading any of my boot disks. Bummer. Next step: Check the heads & hope I didn't break one.
💾

Well, that's it. The heads look good & clean, & they're on right, all the cables are firmly seated right, the belt's having no trouble turning the spindle, & all but one of the boot disks I tried are good & readable. I changed drives & moved the belt to it, & same thing. The computer's just refusing to boot.

@pettancow I did that about 8 years ago for basic data rescue. ISTR these types of HDDs draw more amps than later IDE drives, & I had a hard time finding a 3.5-2.5 adapter that could pump enough juice.

@arielmt Oof, power-hungry disks D: Well, using a straight mechanical adapter with a PATA card would hopefully mitigate the limits a USB-based one would have

@pettancow Yeah. TBH, I forgot how much; the one I have that booted a few days ago draws 700 mA.