Fixing Floppy-Drives

Started by Shining, 00:45, 13 January 15

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Bryce

Hi CPC_Fan,
     how's the family... (oops, not facebook)...

Just fixed your drive. Turned out to be a few grains of dirt embedded into the head. The bad news is that it has probably destroyed any disk you've tried on it. It certainly shredded the surface of the disk I put in to try it  :( I managed to remove the dirt and polish the head and it's working fine now. On top of that, the wires from the index sensor were trapped in the loading mechanism. This didn't cause it to fail, but it wasn't helping either.

I'll try to get your drive back to the post by the weekend.

Bryce.

CPC_Fan

Hi Bryce,


So glad to hear that the drive could be repaired and it was a relatively simple fix. Not sure how the dirt got embedded into the head or indeed how the wires from the index sensor got stuck in the loading mechanism? I hope that it didn't shred a disc that was of value when you tested it?


Would you still be able to make the switchable AmsDOS/ParaDOS ROM, complete with switch and socket that will go into my socket on the motherboard for me at all and send it back with the drive?


Anyway many thanks for looking at and repairing the drive for me Bryce, it is much appreciated.


Mark

Bryce

Oh yeah, forgot about the ROM. Then give me another day or two to get that done then I'll send everything back together. I'd like to test the drive for another day or two anyway, because I found a disk last night that it had problems reading. It may need some minor further adjustment.

Yes, unfortunately it WAS a disk that I should have known better not to have put into a questionable drive. It was a "They Sold a Million" disk (with Jet Set Willy and Sabre Wolf). I'll just change the inards of the disk and re-copy the files over.

Bryce.

CPC_Fan

That's ok Bryce. Not a problem if you need more time. I would rather that you was happy with it and sure that it was working properly, than send it back to me when it's not quite ready. Sorry that it ruined one of your discs. I obviously didn't mean for that to happen.


Mark.




Bryce

Quote from: CPC_Fan on 20:08, 13 February 15
Sorry that it ruined one of your discs. I obviously didn't mean for that to happen.

It's my own fault for doing something that stupid.

Bryce.

TFM

No. IMHO one can't imagine that dirt destructs a disc. That's terrible. I'm sorry. to hear.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

pelrun

Looks like my drive just arrived at read-fail-land. Been having some PSU issues, so that may have hastened its demise. :(


Bryce, would you care to take a look at it for me please?

Bryce

No problem. Have you checked what it will cost to get it to me?? Let's do some "Distant-Diagnostics" first (I'll send you a PM) to see if we can get it fixed without it leaving AU.

Bryce.

pelrun

Well, looks like it was drive speed after all. My dodgy PSU must have been slowing the motor enough to have it mostly work; replacing it brought it up to 309 and stuff broke. Now it's reading 301 and even the previously marginal discs are ok again.


Cheers!

Bryce

Great, fixed without a trip around the world :)

Bryce.

Edit: In case others are confused - I sent pelrun a list of stuff to check before he sent it all the way from AU to me.

the KING

I really love the spirit here. Bryce, you seem to be a very kind person with all the help you provide.



Tom

TFM

#61
Interesting! How can you adjust the rpm's of a drive?

@Bryce: Would be nice if you can post this Drive-Check-List here too. Guess this will help a lot of people.  :)

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Bryce

#62
@the KING : The aim is to keep retro hardware alive, not to take peoples money. If I think something can be fixed "remotely", then that's the obvious first choice. If I suggest sending it to me, it's only because I don't think that the owner will be able to fix it with the tools / skills available.

@TFM : There is an excellent page here from @gerald that shows how to adjust the speed for all different types of CPC drive:  Amstrad FDD part - CPCWiki
Together with the speed test software from @pacomix : DskTest v0.1.47b (release?) anyone can calibrate the drive spin speed themselves (if that's the problem).

My "Checklist" is normally just:

1 - Does it power on at all? (or cause the CPC not to boot if connected)
2 - Does the drive spin up?
3 - Does the head search (ie: move back and forth)
4 - Make strange noises?
5 - Have you checked that the belt is ok?

If I get a "No" on 1,2 or 3 or a "Yes" on 4, then I need it here - It's something more complicated. Otherwise I go through the steps of calibration and head cleaning with the user. If that doesn't solve the issue, then it still needs to be sent to me.

On Classic CPC drives, the most common problems are spin speed, head damage, worn out mechanics and electronic failure (in that order). On Plus drives there is an over-voltage diode that fails most often and after that it's the same failures as with the classic drives. The electronic failures are very often just dry solder joints and not parts that have failed. CPC drives are actually extremely robust.

Hope that has helped someone. Maybe I should do a drive repair page for the Wiki.

Bryce.

Bryce

Another day, another drive. This one came from a user that was given it (for free as far as I know), but the previous owner has hacked away at it quite a bit, so I thought I'd share some pictures of some of the strangeness.
Other than being extremely dirty it supposedly could CAT a disk but doesn't load files, but I haven't connected it up yet, so I can't confirm that just yet. There were some (badly) re-soldered joints on the PCB and the LED pins were freely floating rather than soldered, but I fixed them before I thought of taking pictures. Here's the other stuff I found:

- The belt had been replaced with a tape drive (square belt), instead of the flat type needed. Not necessarily bad, but it rubs occassionally against the casing so the spin speed isn't stable.

[ You are not allowed to view this attachment ]

- Unfortunately he seems to have lost the write pin while he was at it, so it's a read-only drive at the moment too.

[ You are not allowed to view this attachment ]

- Now the best bit. If anyone can explain to me what this is meant to achieve, I'm all ears. This tiny pin (it's half of a bent sewing needle). Was heated and pushed into the plastic eject button. It also looks like it had been tried twice, or maybe there had been a second pin at one time that has since fallen out?? The eject button spring was rattling around on the top of the PCB, but that still doesn't explain the pin.

The pin:
[ You are not allowed to view this attachment ]

Where it was inserted:
[ You are not allowed to view this attachment ]

Although the drives frame is quite rusted, the drive head actually looks quite good after cleaning.
[ You are not allowed to view this attachment ]

So the drive can be saved. But it needs a new belt, a write pin, a resolder on the PCB connectors and LED, greasing on the frame and spindles and then it needs to be recalibrated. Of all the drives I've fixed lately, this is the first time I've asked myself, is it really worth it?[nb]Yes! Of course it's ALWAYS worth it :)[/NB]

Bryce.

VincentGR

This is my drive  ;D

Yes, last October two friends gave me their cpcs.
One here in Pireaus and one 380km far from here where I work half of the year.
They know how wierd I am with old computers and they dig to find their chilhood machines for me.
I always buy and never sell.

The bad thing is that I forgot to bring the other cpc with me but I will send him on summer when I go back there.

Bryce, don't be surprised. Here electricians were only repair tvs, so I have seen wierd things too myself.

The best thing ever donated to me was an A500+ with ram expansion and a 1084 from my wifes friend.
She gave me the amiga the day of my marriage 4 years ago  ;D
Best present ever.

Bryce

So I assume I should continue repairing this? I'm just glad he never tried to fix the 6128 you sent me, it's also a bit dirty, but at least no-one tried to fix it with "Voodoo Doll" methods :D

Bryce.

VincentGR

#66
Quote from: Bryce on 22:29, 21 March 15
So I assume I should continue repairing this? I'm just glad he never tried to fix the 6128 you sent me, it's also a bit dirty, but at least no-one tried to fix it with "Voodoo Doll" methods :D

Bryce.

Wait till u see the other cpc.
I saw the bottom pcb and it has custom traces...
Then u ll reconsider about the voodoo method    :D

Bryce

Drive fixed except for write-pin replacement, now CATting and reading any floppy I care to try. I'll do the write-pin later in the week when I have time.

Bryce.

pelrun

#68
I finally got the 6128 out again with the goal of dumping all my disks to images for use with the Gotek I just flashed with HXC.


Can't get the gotek working; permanent disk missing error no matter what I do with the configuration or cabling. Ugh.


Disk drive starts throwing read fail errors. Ugh. At least this one I know how to fix, so I jump through all the hoops to load DskTest from my tape cable and tune the drive speed.


Drive speed doesn't change, then it changes by 60 rpm, then it doesn't change, then it goes to 500rpm permanently, then I manage to BREAK OFF THE TRIMPOT INSIDE THE DRIVE MOTOR.


AAAUUUUUUGGHHHH.


Moral of the story - make sure you use a *narrow* flat head screwdriver. This time around I used one that was way too wide; even though it fit in the adjustment hole it didn't fit in the slot in the trimpot.


I popped the top off the motor and had a look inside; apart from the free-floating trimpot and a couple of bent brush fingers everything seems ok. I'll get a replacement 10k pot tomorrow and see if I can't successfully reassemble the thing. I don't expect it to last; I just want it to run long enough to get those disks dumped...

pelrun

I managed to repair the motor and get it reassembled - a somewhat tricky endeavour, as you have to remove the capstan and get the spinny thing out to safely get the commutator together without damaging the brushes. Anyway, a sharpened nail and hammer did the trick.

And now the drive makes a horrible squeaky noise, almost certainly due to the motor running backwards. Just to check - discs are meant to spin clockwise, right?

I'm going to hate pulling this motor apart again just to swap the brushes over...

Bryce

How did you manage to get the motor running backwards?? Have you connected the wires the wrong way around?

Bryce.

pelrun

As there's a speed controller inside the motor reversing the external wires won't work. The only thing it can possibly be is I got the brushes going the wrong way around the commutator ring, which is nuts because there's a very obvious brass contact patch on one side of each brush.


I've little choice (beyond sourcing another motor) but to open this one back up and swap the brushes over.

pelrun

Opened the motor up again and swapped the brushes over, checked the motor runs the correct way, then tried again. It works!


Bryce

Hi all,
   sorry for resurrecting a relatively old thread, but I thought I'd keep this information all in one thread to make it easier to find...

Last night I recieved two floppy drives for repair. Once again the owner informs me that he sent them to Dataserve for repair and they were returned as "unrepairable". I haven't tried to fix them yet, but even a simple first look tells me that the guy didn't even attempt to repair them. There are obvious dry joints on the header connectors and the motor capstan is full of gunk from the old belt. So he obviously just blindly swapped the belt and sent it back and he also obviously doesn't have the first clue about electronics. He did however charge for a supposed attempted repair.

So my message once again is DON'T SEND DRIVES TO DATASERVE FOR REPAIR. He is NOT repairing them, he's blindly swapping the belt without even cleaning the wheels and then sending them back as unrepairable if that hasn't solved the problem. And charging you good money for it.

Bryce.

Gryzor

That's a shame, kind of you to let everyone know. Do we know how much it was for the "attempt"?

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