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Need help with IBM 5150 5.25 drive having trouble writing

I dont think Windows corrupting 360KB disks from a 360KB drive is an issue here. The OP posted in another thread about formatting disks and was able to get the drive working in the past. Its either a hardware issue or the disks hes using (although I think thats a hardware issue too isnt it :unsure:). Without a spare its tough to test. With this post you can see he has an original IBM low density floppy controller. Sometimes the Controller IC fails. Sometimes the TTL logic on those boards does: https://forum.vcfed.org/index.php?threads/ibm-5150-3-5”-formatting-at-360k.1239256/post-1265486

I still suspect the drive. He was able to get the 3.5" drive writing and formatting on the same card so it seems the drive is the culprit.

He bought the disks from Glitch. https://forum.vcfed.org/index.php?t...es-boxes-of-10-with-sleeves-and-labels.61929/
I have bought hundreds of these same disks with no problem... Really they are all NOS and wrapped. I havent had a problem yet. So I am leaning towards the drive or floppy controller.
 
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I dont think Windows corrupting 360KB disks from a 360KB drive is an issue here. The OP posted in another thread about formatting disks and was able to get the drive working in the past. Its either a hardware issue or the disks hes using (although I think thats a hardware issue too isnt it :unsure:). Without a spare its tough to test. With this post you can see he has an original IBM low density floppy controller. Sometimes the Controller IC fails. Sometimes the TTL logic on those boards does: https://forum.vcfed.org/index.php?threads/ibm-5150-3-5”-formatting-at-360k.1239256/post-1265486

I still suspect the drive. He was able to get the 3.5" drive writing and formatting on the same card so it seems the drive is the culprit.

He bought the disks from Glitch. https://forum.vcfed.org/index.php?t...es-boxes-of-10-with-sleeves-and-labels.61929/
I have bought hundreds of these same disks with no problem... Really they are all NOS and wrapped. I havent had a problem yet. So I am leaning towards the drive or floppy controller.
Hopefully the OP will find and fix whatever is wrong with their system, and then report back on the cause so others might benefit. I find it humorous to a certain extent that we're spending as much or more time debating what could be the fault as the OP would spend proving or disproving a case of disk corruption. The list of things that could be causing the observed fault would be long. Proper troubleshooting technique would include starting with the most likely fault and/or easiest, least disruptive testing. It is what I did professionally for 40+ years and taught from time to time for most of that.

"And that's all I have to say about that." -- Forrest Gump"
 
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I don’t have any means of checking these disks in a windows based system. I am in the process of acquiring another drive to test. I’m kind of leaning toward this being a drive issue. I’ll update with my results.
Thanks
 
Id like to thank everyone for their inputs on this matter. I was able to get a known working drive and swap mine out and all disks seem to format properly now with the new drive. And I am able to write to the disks and the files appear in the directory. The issue might be in the PCB on the drive. That will be another project, but for now I have a working drive.
Thanks again
 
I have at least four old 5.25" floppy drives that won't read a diskette. I think one is a 360k and the others are 1.2M. I also have three 5.25" drives that are working. I've had better success with 3.5" 1.44M drives

Thanks for reporting on the fix to your problem. Let us know if you are able to fix the non-working drive.

Seaken
 
I didn't read every response so maybe this was already asked: Did you try cleaning the drive heads?
 
Heads and rails have been cleaned twice. Im looking into the possibility of the terminating resistor pack on the PCB causing an issue. A SAMs manual mentioned formatting a disk and if it has trouble formatting, the resistor pack at 2F is a possibility. I saw once someone on the forum was having a hard time finding one. I am planning swapping the one out of the working drive to test and if that happens to be the issue I’m going to need to locate one. I agree I don’t think this is an alignment issue.
Thanks
 
Heads and rails have been cleaned twice. Im looking into the possibility of the terminating resistor pack on the PCB causing an issue. A SAMs manual mentioned formatting a disk and if it has trouble formatting, the resistor pack at 2F is a possibility. I saw once someone on the forum was having a hard time finding one. I am planning swapping the one out of the working drive to test and if that happens to be the issue I’m going to need to locate one. I agree I don’t think this is an alignment issue.
Thanks
Tell us what the resistor pack looks like maybe a photo and maybe someone on here can help you track down a replacement.
 
The resistor pack is usually a single inline or a dual inline package. They are not usually difficult to find.

The last drive in the chain (the furthest away from the disk controller) should have a terminating resistor pack. All other drives should not have one fitted.

Dave
 
Thanks Dave,
Could you possibly direct me to one with a link? Here’s a pic of it
Your drive is a Tandon TM100-2. The terminator for that particular drive is described in the diagram at [here], with the description including a couple of model numbers that you can use to search for online.

If you have a multimeter, you could use that and the diagram to determine if your existing terminator is good/bad.

Also, in case of poor connection between the terminators pins and the IC socket, try removing-then-refitting the terminator a few times.
 
Some interesting stuff posted today on this thread.


"Note here: DO NOT format a floppy on a Windows PC if it is to be used for DOS on a vintage computer. Windows formats floppies in a way that makes them unusable on a DOS machine. I used a floppy that was formatted from the factory. Fortunately, it was still usable. Now I format any floppies I need in the Compaq before transferring any files or images to in on the Windows PC."

I swear I've heard that before someplace.

;-)
 
Thanks but I don’t think that can even happen accidentally here. I can only format disks on the 360k drive that’s in the 5150. My USB drive is a 3.5 and I even format those disks in the 5150 as well. The new drive seems to be working good. I’m looking into some possibilities why my original drive is acting up. I removed and checked the termination resistor network and it’s showing 150ohms between opposing legs like it should. I’d rather not blindly start desoldering all the logic chips to test each one unless I had some sort of direction. But it doesn’t appear the network is faulty based on my testing. I will swap the one from the working drive just to confirm.
Thanks again
 
If you have measured the resistance values with a multimeter (and checked adjacent resistors for short circuits) then that is the best you can do.

You can fault find a little bit further on the drive (without desoldering components) if you have access to a schematic for the disk drive concerned and the appropriate test equipment (e.g. a logic probe at the least or an oscilloscope).

Dave
 
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