X68000 Compact Floppy drive "extreme" repair

Started by aje_fr, April 17, 2021, 10:14:49 AM

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aje_fr

Hello there,

I just wanted to write a tutorial about how to service X68000 compact floppy drive.
Those drives are known to be kind of capricious.

Few tools are needed to service them but you'll also need extreme patience and time (nearly 1~2 hour per unit).
Swiss jewelry may be easiest to repair compare to some parts of this drive.
Take pictures while disassembling the drive to help you with reassembling.

I will not be responsible if you destroy your drive, loose parts or something else, try this only if you are able to do this.
You'll need precision tool and microscope for some parts

Problem encountered with these drive are : stop working during reading, disk eject, not reading, ...

It helps me to repair 4 drives (all had similar troubles)

I'm sorry, I don't took all necessary pictures, I will update thread if I'll take more.
English is not my first language so please pardon my errors.

Let's start easy thing :

Separate both drives :


Then, you have to remove top cover.
There is 4 tab to lift (I have not took picture, you should not have drives attached together) :


You have one screw to remove near the connector :


Remove the head motor cable :


Gently lift up the PCB, remove the white flat cable.
Remove also the heads cables, takes extreme care to this cable, they are very fragile. You have to remove white tape.



You have to disconnect the eject system connector and track 0 sensor connector :



On the front of the you have to remove the led/switch connector :


Now, it's time to remove some leaky capacitor (I'm using ceramic capacitor instead of electrolytic) :




Now, let's go deeper !

First, remove the eject mechanism motor :
There's to tiny screw (on the right of the picture), they are different, don't switch them.


Then, you'll need to remove floppy disk rail, take a flat screw driver and gently press between metallic part to lift it up :



Your drive should now look like this :


Remove the spring


To remove the bottom rail, you have to lift up the eject springs and slide the rail to the back :
The track 0 sensor may annoy you a bit but do not remove it !



The drive should looks like this :


Remove all the screw that maintain the last PCB :


There is 4 screw to remove under the drive, use a pen to mark the sensor position :


Push the center to remove the rotor (it may be easiest to remove the rotor before the top screw) :


Now remove the switch (funny thing to come), one is glue with double side tape :


It now should like this :
You can now clean the head. Take care about not twisting the top head suspension.



You have one capacitor to change (I put a ceramic one but it must be very thin, it may be easiest to use a electrolytic like the original one) :



Now, here comes the hardest thing !
The trouble in those drives are the tiny switches used to detect the disk, it's type, write protection.
You can check it with a multimeter, the electric contact may be bad while pushing them.
Desolder all of them (take care, there is two different kind).
TAKE EXTREME CARE, ANY TINY PART LOST AND YOU'LL BE UNABLE TO REPAIR THE DRIVE.
You'll probably hate me for starting this.

I will show you the two contact one :



Gently lift one side :

Now you have to take extreme care, there is very very tiny parts and springs that can be lost.
Lift, the other side :


It's time to clean the bottom contact of the switch (use thin sand paper or contact cleaner) :


Next one is the electric contact inside the push tab (contact cleaner and/or sand paper) :




As I told you, parts are really tiny:


Take care that while reassembling buttons, you'll have to put the spring inside the white tips :
One switch have two buttons, the other one, take care about orientation.


Once done, you can solder back the buttons to the PCB in the same way they were.

It's now time to reassemble the drive ! Like it was disassemble !

Few tips while reassembling.

The head mechanism should be reassemble that way :


Head cable should be tape back :




Once drives connected back to computer, you'll have to test it with good working floppy disk.
You must have a working scsi drive (or scsi2sd) with the FDR68K tool
https://nfggames.com/X68000/index.php/Misc/Diagnostics/FDR68K%20v1.0%20by%20Kamiboy/

If the drive is working, you'll have a screen full of O


If not, and the drive start with X :

First things to try is to gently press the head, if it starts to fill with O, move the head springs from :

To this position :

If you still have trouble with the top head :

You can try the last position :

And that's good :



Now, it's time to have fun !



That's all.

Dedicace to M&T

stas2k

Thanks for taking your time in posting this. I have one dead drive in my x68k that I want to try to repair. For now just opened it and cleaned as it was very scary to do what you described here :D

hlide

#2
C'est clair... que ├ža fait peur !

Clearly... scary!

I have a CZ-6FD5 which has a drive needing a repair (no led, no ejection, only motoring a second when inserting disk, no reaction otherwise) but by just looking at that post I found it scary.

Cyothevile

Aje_fr,


Is the capacitors inside each FDD:

10uF   10v   x3
47uF   6.3v   x1

I will try to find tiny electrolytic. If not I will get tantalum or ceramic capacitor. Side note my ribbon cable, the metal teeth seem damaged so I can find the replacement. I will post the part number.

aje_fr

Quote from: Cyothevile on April 18, 2021, 11:15:47 AMAje_fr,


Is the capacitors inside each FDD:

10uF   10v   x3
47uF   6.3v   x1

I will try to find tiny electrolytic. If not I will get tantalum or ceramic capacitor. Side note my ribbon cable, the metal teeth seem damaged so I can find the replacement. I will post the part number.

Yes on the top board :
10uf / 10V   x 3
47uF / 6.3V  x 1

But on the bottom board, there is also :
10uf / 10V   x 1

squeeb

X68000 SUPERHD

dlfrsilver

#6
Hi Aje, i followed your tutorial, and thanks for sharing it, i have been able to unlock my second drive on my compact.

I'm stuck on a single part : what tool do you use to unscrew the sensor that you marked with black pen ? I have searched in my toolbox, and i have nothing matching .

Do you have a reference tool to propose for that ? :)

Thanks !

aje_fr

Here is the tools I used :
ESD-14 tweezers :


Precision screw driver for the sensor screw (i think it was the torx T10 or T15):


And another box of screw driver for all other screw :

dlfrsilver

Thanks a lot, i picked a set like the one you presented :)

nice, i will be soon testing my X68000 Compact ! :D

kamiboy

Haha, you are using the floppy realignment test tool I wrote almost 10 years ago. What a blast from the past, to think someone is actually using that tool, that is pretty cool.

I remember I did this sort of extreme maintenance on a whole batch of compact floppy drives back in the day. These drives are extremely finicky and failure prone. My experiences led me to conclude that it is impossible to actually get them to work 100% factory fresh once they start failing. The 5.25" drives in the full sized towers are much more robust in that sense.

famiac

kamiboy, i still use your tool :)

both 5 and 3 inch drives have their upper magnetic-read-head assembly resting on the metal case with a one-sided support. i have gotten drives to work better by twisting the upper read head in the opposite direction, since they get torqued over time by sitting idly.