8088 era floppy disk diagnostic

[RetroHospital]

Hello everyone,

I revived a Tandy 1100FD, this is a V20 (i8088) era laptop

After much work , teardown, cleaning, floppy belt replacement, retro bright, it's working properly except for the 720KB floppy drive, that can "somewhat" read half a floppy before doing read errors.
They appear at random (some floppy that couldn't be read, can be read later on)
It's unusable.

i'd like to know more about the problem ( speed or head ), could anyone recommend a 8088-era floppy disk diag tool ?

Thanks !

 

[SomeGuy]

What you probably want is ImageDisk. It has an "alignment" mode that you can use to move the head over a track and constantly read, showing you what it thinks it has read. Even if it is not an alignment issue, it is useful to leave running while you poke around for intermittent issues.

 

[Trixter]

To add to that, ImageDisk will show you the rotation speed of your drive. If it's more than +/- 5 RPM away from optimal, you can adjust the speed pot on the drive to fix it.

 

[bolex]

Tandy had Tandy Drive Controller - which was designed to align floppy disk drives found in Tandy computers. It's on this Tandy Diagnostic Disk.

 

[bolex]

Radio Shack's video on how to align a floppy disk shows how to use the software in this video.

 

[syzygy]

They appear at random (some floppy that couldn't be read, can be read later on)
It's unusable.

In addition to the good advice you have already received, I want to stress the importance of repeated cleaning of the heads, IF you are testing a number of old disks. I recently went through resurrecting some floppies and, of course, I checked the timing (using those tachometer/light displays at the least) and I cleaned the heads.

But, I would get similar "it worked and now it doesn't work", what's going one? In my case, what was going on was I was testing 30-40 year old floppies that were dirty or even degraded and the heads were getting dirty. Your situation may be different, but, I would underscore the need to clean the heads again if you are using a lot of old diskettes.

Coincidently, just today I located an old shareware DOS program that will give the timing on 8088 PC drives. It seems to work ok and it lets you step the drive up and down, but you have already been given info on some others.