800k floppy works, but not very well

[JeffC]

I recently took an old Plus out of storage, it hadn't been used in probably 25 years. I took the 800k drive out today and cleaned and lubricated it, I also very gently cleaned the heads with 99% alcohol and a q-tip. I didn't loosen the screws for the motor, so I shouldn't have un-aligned anything. The drive reads somewhat ok, but can't successfully format a disk or copy files to a disk without errors. When it reads it sounds like it's struggling sometimes, it makes that noise I remember floppy drives making when they are having trouble reading - a pause, followed by a different tone, and then it goes back to reading the disk. I didn't test out the drive much before I cleaned it, so I don't know if it had the same problems before the cleaning. Are there any common issues that could cause this type of behavior?

I also have a working 800k external drive, both it and my Plus internal drive have the yellow ribbon cable. Is there any reason I can't just swap the drive from the external enclosure into the Plus?

Thanks, Jeff

 

[Kai Robinson]

Hi Jeff - it might be that this can fix your issues:

https://tinkerdifferent.com/resources/zero-track-alignment.37/

 

[JeffC]

Thanks Kai, that looks interesting, I'll give it a shot.

 

[JeffC]

I followed the instructions in the zero track alignment file, and unfortunately I seem to have made things worse. Following the instructions I was able to determine the zero-track sensor adjustment allows for 5 distinct "steps" (starting positions) for the read/write head. Based on the info in the file, with the sensor all the way back, if we call this "-3", this means my 5 steps should cover tracks -3 through 1, and the fourth step should correspond with track zero, as stated in the instructions. Unfortunately no matter which starting position I set, I get the same result - when I insert a known-good boot disk, I get the floppy icon with the X, and the disk is automatically ejected. I tried with the sensor set to each of the 5 possible starting positions multiple times, and I got the same result each time. I also hooked up one of my external drives and confirmed that it was able to boot with the same boot disk I was trying in the internal drive.

I'm not sure how the drive could have semi-worked before this procedure, but is completely non-functional after. I didn't touch/adjust anything in the drive other than the zero-trac sensor. Any thoughts for further troubleshooting? I wonder if I could have damaged the read/write heads somehow when I cleaned it. When I first started my cleaning, the two heads were stuck together. As gently as possible I pulled the two apart, but I could tell this was putting some strain on the wiring that connects the upper head. Somehow something sticky seems to have gotten between the heads, once I cleaned them they weren't sticking together any more.

I also realized my internal drive has the yellow stripe cable, and both my externals have the red stripe cable, so unfortunately I can't just use one of those as an internal.