VOGONS


First post, by GabrielKnight123

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This Asus PCI/I-P54SP4 AT motherboard has a problem with a connected 3 1/2 1.44mb floppy drive its set in the bios to 1.44mb 3 1/2 it can read a floppy but it cant copy or write to it it says "sector not found reading drive A Fail on INT 24", I am using good floppy disks I tried scandisk on a good one with a surface scan after initial checks and it said the FAT media byte was missing so it replaced it and there were no bad sectors, the files were still on the floppy so I tried to copy to and from it but with the same error, I formatted the floppy with just "format a:" and it formatted it at 360K and not 1.44mb but I could read, write and copy files to and from it, I tried specifying 1.44 like "format a: /f:1.44" but it said "parameters not compatible, format terminated".

I looked over the motherboard and saw underneath the board are two resistor banks soldered to the secondary IDE and a wire that goes to another resistor bank on the parts side of the motherboard which also connects to the floppy connector, does anyone know what this mod is for and if I removed it would it fix my floppy problem? I haven't connected anything to the secondary IDE yet so I don't know if it has problems too but the primary IDE with a hard drive is working fine.

I've tried a known working floppy drive but it doesn't like being connected to this board when I do a simple "A:" the drive groans and moans and wont work

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Reply 1 of 5, by Datadrainer

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I don't see a problem with the floppy connector.
The resistors network are connected to the reset and data bus lines. I think they act as a terminator to minimize bus interference.
The common pin (pin 1) being connected to the ground of the other (top) resistor network. I see nothing interfering with the floppy circuitry. But maybe there is a short, or a cut trace somewhere. You can check the continuity between ground and signals with no drive connected on IDE and floppy connectors.

Knowing things is great. Understanding things is better. Creating things is even better.

Reply 2 of 5, by Deunan

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GabrielKnight123 wrote on 2023-03-02, 11:14:

I tried scandisk on a good one with a surface scan after initial checks and it said the FAT media byte was missing so it replaced it

And that might be why DOS sees the floppy as 360K. Don't let ScanDisk "fix" things that are not broken. Use Norton Disk Doctor instead if you have this issue.

In general: DOS is stupid. It writes proper media header on the floppy but will only ever use the media byte or a BIOS drive type and hardcoded values for access. Try formatting a floppy (that has not been "fixed" by SD) with /U param, see what comes of it, but this might be a software issue, or a subtle hardware issue that causes DOS to mis-recognize the floppies.

Reply 3 of 5, by GabrielKnight123

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I checked if there was a short for both IDE and the floppy connecter and there were none, would it matter if dos was not installed to the hard drive through this motherboard it was installed on another motherboard and I connected it to this one

Reply 4 of 5, by Datadrainer

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What matters is how the BIOS is configured. If you replace your hard drive, change the setting in the BIOS config utility accordingly, or if applicable check the drive is auto-configured correctly. It is the same for the floppy disk drive. Check if its configuration is OK, sometime setting 1.44MB is not enough. If you do not know what to change, please provide us some screen shots so we can try to help you looking at the options available.
Another thing to do is to check your cables. Those old ribbon cables are sturdy but after a lot off plugging/unplugging incorrectly the top of the plug itself can break and pop off, loosing some wires connection. The plugs contacts themselves can corrode too. So that's always a good idea to check the cables and to clean them (check online how to do it, there is a lot of resources on how do to it for any type of electrical connection). Also if a cable have multiple plugs, the plug used to connect the drive matters, especially for a floppy drive.

Knowing things is great. Understanding things is better. Creating things is even better.

Reply 5 of 5, by GabrielKnight123

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For now I've given up on this motherboard I tried using an ISA I/O card to see if I could get the floppy to work which it did work but then I connected a CD rom to the motherboard secondary IDE and I cant get it to boot fully it freezes after the ram count and the energy star in the top right hand corner stays too, I've tried removing all drives and loading bios defaults, reseating bios and CPU and ram but she wont boot so its going in a box for attention later in about 50 years or more, I hate this board but the bios options are good one thing I haven't tried is a bios update