INT 24 DOS error message

[gottjoe]

I'm trying to revive a CompuAdd laptop that has DOS on it. When these were originally sold, they came with Windows 3.1 installed. What's holding me back from reinstalling Windows 3.1 is that I can't get the floppy drive to work. I always get a Abort, Retry, Fail message when trying to access the floppy. I do on occasion get the Fail on INT 24 error message from DOS when trying to format a floppy disk.

I should also mention that the floppy drive that came with the laptop had a bad capacitor that I replaced. That didn't help. The replacement floppy drive I purchased also didn't make any difference. I still can't get the drive to pull a directory, or format a floppy. So today I ordered a 34-pin to USB floppy adapter from Amazon. I want to check these drives outside of the laptop.

Has anyone run into this issue with a perceived faulty floppy drive that always gives errors even when the floppy has been replaced with a hopefully working floppy drive?

Thank you!


Joe

 

[krebizfan]

Which model of CompuAdd laptop is it? It is possible that someone could recognize that model and determine if it needed a special driver (VXD) for Windows.

If it occurs with multiple drives, I would suspect the cable. The controller might have been damaged by ESD but there is nothing that can be done in that case. Having a laptop with a failed floppy controller that otherwise works is an unlikely occurrence.

My quick research does show some claims that a specific virus could trigger INT 24h errors so double check that the disks used don't have any virus. Another unlikely cause but it makes things simpler to confirm that it isn't the problem.

 

[NeXT]

Can we get a specific make/model for the floppy drive just to verify if there's a way to substitute another drive relatively easily?

 

[gottjoe]

The laptop is a CompuAdd 316SL with the floppy being a Epson SMD-1000 that gets its power from the ribbon cable, not a power connector (this is a first for me to see).

While taking out the hard drive that appeared to have crashed, and trying to test it on a PC via USB connection without success, I was putting it back into the laptop when I saw something on what I'm calling a "controller module board" that I had to unplug in order to get the drive back in place.

Something fried pretty good on this board in the past (see photo). I really don't know if it's part of the floppy drive problem. I have no documentation, and I have not been able to locate any on the internet.

Now after putting everything back together, the hard drive decided to work again and boot DOS. The floppy still has a problem, but it appears to be at least trying to read and format a disk. I think it might be fixable if I pull the floppy again and replace the one capacitor that I didn't replace on it.

This link is helpful. http://asknotes.com/2021/03/15/fixing-ep...isk-drive/

What I also discovered with the laptop floppy drive is that it has no power connector unlike the replacement I had purchased. It gets its power from the ribbon cable somehow. I've never seen this before. So I was unable to externally test it with the USB to 34-pin floppy drive adapter I purchased. The replacement worked fine since it has the power connector. The strange thing is that both of the Epson floppy drives have the same model number.

The laptop also does not appear to be charging the battery. Given the age of the unit, I'm not surprised.

I'll update this post as things move along.

Joe

 

[krebizfan]

Not all of us have joined HP Museum making the picture a bit difficult to see.

Pictures of the end of the floppy cable could show which pins have power. The floppy drives powered through the data cable have connections to the standard power lines within the drive; the entire drive isn't reworked. That is based on the drives I have seen. I am sure someone will be able to remember a drive that did it differently.