400 k drive missing felt

[bibilit]

I have been trying to repair a 400 k floppy drive.

Was stuck hard in the first place and managed to get  the carrier free, in order to have a nice insert and eject process.

Problem is, i spotted the small upper pressure felt was missing, so in operation the unprotected plastic is scratching the upper part disk.

The drive is not working, can ear the floppy acting, but the floppy will not find the system.

Anybody has found a way to replace this felt pad, and can be this missing part responsible for the drive not locating the information on the disk ? 

 

[BadGoldEagle]

As I'm sure you already guessed, the pressure pad applies pressure to the disk. If uneven pressure is applied then it will definitely have read issues. On a good, working drive, the disk will wobble a bit with the pad lifted and it won't work properly. The felt needs to be in place to get the right balance. I know that because I misplaced the felt when I relubed my drives... They didn't work until I put the damn thing back in.

As for getting a new felt in there, you could try to get a hold of new audio cassette felt on ebay. I've seen a couple for sale there. Can't find any right now but it looks like this.

Don't you have another 400k drive lying around whose felt you could borrow for an experiment? I mean why bother trying to replace a felt on a completely dead drive...? I have one here, if you want I could drop by your place and we could give it a try...

 

[bibilit]

maybe found a solution, will try first.

 

[bibilit]

drive was given back to the owner, but was thinking can the felt of an Apple II Disk be a suitable spare ?

 

[jsarchibald]

It's not the felt that I am having trouble with, it's the small plastic part that attaches to the felt pad, that then is located in the spring-loaded arm.  There has to be a fix that will be permanent, has happened on 3 of my 400K drives.

 

[Corey986]

OK, I have the same problem.  My external 400k drive I just got and started cleaning/re-lubing is missing the plastic piece that has the felt pad.  I checked thingiverse and no one has made one on a 3d printer yet.

Anyone have an alternate source for this part or what other drives can be "donors" except a rare 400k drive?

Thanks,

Corey

 

[Byrd]

I can source sticky backed, hard-packed wool felt through work (health) in 3/5/7/10mm thicknesses.

Anyone want to post a pic of the item in question?

JB

 

[Corey986]

For felt I was just going to use the felt from a new audio cassette cut down. That is what I have used in the past for non-Mac drives missing felt.

I looked around my workshop for anything that might be used to replace the missing plastic piece so I wouldn't have to scrounge one from another drive.

I took the end plug of a IC tube that splits at the bottom to hold it into the tube and cut off one of the split sides so that it will fit in the hole where the plastic piece should go. It makes a nice platform for the felt that can shift and spin like the original missing one. I just isn't beveled to hold the felt so hopefully contact cement will hold. After I put it in the hole I squeezed the piece that fit though the hole so it won't come out.

I hope that makes sense. I'll glue the felt on tonight and try it on Tuesday. I have too many work things tomorrow.

Hopefully someone has a better solution. If not this hopefully will be it.

Cheers,

Corey

 

[Corey986]

Just realized I should explain this better. Not sure a picture will do now that it is installed because I picked a black plug. The plug isn't one of those rubber things but something that looks like a plastic thumb tack so that it can provide a flat surface to glue the felt to. It then splits into barbs that are pushed through a round hole in an IC tube stoping the chips from sliding down. I had ones that split into a barb on top and ones at the bottom. I used one that splits at the bottom so I could cut the barb down to fit by removing one side and shaving the edges a little.

Just used contact cement to put the felt on and a junk disk to put pressure on it till tomorrow. So far so good. Will let you all know if it works and then I'll see if I can make another one and take pics as I make it on a white background so it comes out in a pic.

 

[Corey986]

Here are some pics of the piece I made installed.  Still have to take pics on how to make it for those interested.  

 

[Johnnya101]

Looks great!

 

[Corey986]

Works perfectly.

I hooked it up without a case to watch it to make sure the felt sits flat on the disk to put even pressure.

Initialized a couple of disks and copy data and flipped the disk between the internal and external drive a few times. Worked perfectly.