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Maybe your cable is defective?

I've already tried a diferent (more recent) cable with the same result. I suspect, maybe the cables are diferent. Is that possible?

pdmelo wrote on 2021-03-16, 22:45:

I've already tried a diferent (more recent) cable with the same result. I suspect, maybe the cables are diferent. Is that possible?

welcome to Vogons ! Can you take some pictures of the motherboard, floppy controller and cabling ?
I tried finding some good picture of your board but failed.
Are you using an old style cable with the twist at the end ? Maybe you board needs a straight cable. (have yet to find a good manual).
One other thing could be a BIOS setting. If default is A = 1.2Mb drive and you are using a 1.44Mb then you will have an error even if the BIOS sees the floppy drive, it will not be able to read/write to it.

The Model is a Philips PCD 211 286 AT (also known as P 3239). The BIOS keeps detecting, on boot, two 51/4" drives even after I've manually set it to 31/2" HD.

The floppy controller is onboard. The PC came with a MFM Hard Drive and respective controller card but the disk wasn't working so I removed it. The onboard IDE controller works fine.

The Epson Diskette drive came with the computer. I think it was the original diskette drive but I'm not sure.

Thanks for the pictures ! That is one weird motherboard !
My thought: Think it could be the cable as Doornkaat said. Did that cable come with the computer ?
Or the onboard controller has gone bad.
Ok the Epson SMD-300 has jumpers to set Drive 0 or 1, are there any ? Just checking...
Most old computers have a cable that accepts both 3.5" and 5.25". Your cable is not one that can do that, could be why it thinks there is two floppy drives if the jumpers are correct.
It should be set as Drive 1 like in this:

It doesn't show in the photo but the cable has one 5.25" connector.

I've already tried the jumper configurations on the drive has show in that graffic. I also found that same diagram on my searches.

I have another Philips old PC (a 386SX with similiar board and the same BIOS system) where the diskette drive works fine. I've tried that drive and respective cables on the 286 but got the same result.

At this point I won't "invest" more time on the 286. Most likely is a problem with the controller. I've installed DOS in the hard disk (via another PC) and the computer boots works OK except for the diskette drive.

Thank you all for your suggestions.