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Pain in the NEC: Versa M/75 floppy drives not reading squat

retro-pc_user

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SE Michigan, USA
Long story short, I'm trying to get a pair of floppy drives to work in the NEC Versa M/75 (486) so I can install the EXP CD-ROM + SoundNote drivers and TSR software on the hard drive, including games.

I attempted to fix the original drive to no avail and the one that I got off of eBay that was "tested" doesn't work either. Both of these drives are suffering a plague: General Read Error or Sector Not Found. I did clean the heads to no avail and the track motor is working along with the head motor (yes, I greased the rails). I hear clicking noises when I type in DIR A: and it throws either of those errors.

The diskettes work in my other systems without any errors and the drive setup in the BIOS is correct: 1.44MB in size.

Has anyone had an issue with these laptops that cannot read diskettes and where can I find a functioning one or NOS?

Edit: did some cleaning and I took the Ni-Leakium CMOS battery out since it's flat as a pancake (not holding a charge). The original drive works, just not the spare yet.

Edit 2: back to square 1 again. Lemmings won't install at all and it's a hit and miss again.
 
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I have four of these Versa 486 laptops (40EC, V/50, M/75, P/75 (Pentium w/ SB)), LOL. That's about all I talk about on here these days even though I have like, five other vintage PC's. Funny enough the M/75 is my favorite despite not having OPL. My P/75's drive acts like yours, my M/75 is practically mint, the V/50 is also kind of mint, but I have to SLAM disks to get them to read into my 40EC. The V, E, and Ultralite all use an earlier drive cradle and connector but MAY have the same model actual NEC Floppy inside the cradle.

- When you removed the CMOS Battery did you replace it with anything. IIRC, I've had some odd problems with floppy access on NEC Versas if there is no CMOS battery present. You could probably wire in a CR2302 holder to the original battery terminals, or even just wire on a modern laptop CMOS battery to it and it'll work. My P/75 has a battery for Dell Latitudes in it and it works great.

- PCMCIA cards have been known to give me floppy drives issues on these. I use Cisco Aironet LMC-352s on these for WiFi and I find there's some kind of "Soft Conflict", for a lack of better words, that causes odd floppy activity such as not reading good disks. Might help to copy the files to the drive using another computer using a USB adapter, or use a 44pin on one of your other machines to copy the drivers over to the drive to install from as a workaround. This same soft conflict causes the PC Speaker to stop working as well when I'm on WiFi (digital audio, and opl on the P/75, work fine).

- I may have a spare drive laying around. I ordered the earliest version of this laptop earlier this year (Ultralite Versa PC-410 - it's the 25MHz model without the trackball) that crumbled to pieces in shipping and was DOA anyway. It won't fit the M/75 as is, but I can see if the floppy drive inside the cradle can fit - I can check and see the connector on lunch or when I'm at home (I have my V/50 with me).
 
I didn't put in a CMOS battery yet since I never did the CR2032 on a rechargeable circuit other than soldering wires to the external battery header.
 
Well, I added a CMOS battery and it still won't read any diskette I insert. Even without a PCMCIA card installed, the same thing. Cleaned the contacts and the heads some more as well without success.
 
Count me in the club of non-working FD1139H owners now lol. Except I have two, one in a M/75 the other in a M/100, both of which don't even seek despite cleaning their heads and examining their rails. If you're able to find a fix I'd be extremely happy to know.
 
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I took the one floppy drive apart and oiled the shaft for the heads and it's working for now, but it might fail again. I'll post an update the next day.

Also copied the IMD programs to the hard drive so I could run the clean head cycle on the drive. I'll do the other one and see what happens.
 
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I've got similar problems with the drive in my P/75, maybe I'll kick back on the patio some weekend and give your method a try on that one.
 
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