3" Disk Drive faulty? (it is not the belt :D )

Started by pacomix, 21:17, 10 June 13

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pacomix

Hi!


   Recently I got a 3" disk drive from eBay really cheap and faulty from eBay. Hoping that only the belt was the source of the problems I decided to buy it.
   After putting a new belt inside and mounting it in one of the cpc6128 I have I realized it wasn't reading any disks... It was a little bit strange since it always showed me the "Drive A:   user     0" message but then the disc missing one.
   I think that means it found the first track, am I wrong?
   I continued trying without any luck. Then I just touched the plastic piece that makes pressure over the read head and suddenly started reading the disk correctly. It was a really slight pressure, only the weight of my really thin index finger. I can hear slightly how the speed is decrease by the noise it emits.
   I do not know where the problem could be. The disk drive is an EME-156. I have read somewhere that some disk drives of this model spins at 300rpm and some others at 360rpm. But now... I do not know if that could be the problem. I also thought that problem can be that his piece of kunststoff is not doing enough pressure over the read head and I also read that the drives could be modified in order to affect the RPMs so they can copy some protected games.
   Where do you think the problem could lie?


   Any hint would be of great help. I pretended to mount this drive in a PC for preserving tons of games I have...


Regards!

Bryce

I doubt it was a speed change that made the drive suddenly read the disk. It's more likely that you changed the position of the disk or head. Have you already cleaned the heads?

Bryce.

pacomix

Yep! I already cleaned the heads... (well... the head, there is only one) What I can not explain is why when I drop (I am not pushing it) my finger slightlz over that plastic piece it works...

Bryce

Can you take a photo of exactly where you are applying the pressure?

But while you are at it. Have you tried turning the drive upside-down to see if it works like that?

Bryce.

spookspring

#4
Had problem like this, I adjusted the torque of the drive motor. Its obvious where to do it.
It has a turn point of about 1/2 turn, I adjusted this slightly until the disk read.
I believe this might be the Azimuth of the disk drive, like on the tape deck.
The final frontier - trying to get online with a CPC - Complete!

Gryzor

Quote from: Spookspring
Its obvious where to do it
Where? :)

pacomix

Quote from: spookspring on 09:40, 11 June 13
Had problem like this, I adjusted the torque of the drive motor. Its obvious where to do it.
It has a turn point of about 1/2 turn, I adjusted this slightly until the disk read.
I believe this might be the Azimuth of the disk drive, like on the tape deck.


So you mean the speed of the motor, right? To be honest I have no idea where I have to touch... I will take pictures of the controller once I get home .


Quote from: Bryce on 22:10, 10 June 13
Can you take a photo of exactly where you are applying the pressure?

But while you are at it. Have you tried turning the drive upside-down to see if it works like that?

Bryce.



Hi! No I didn't try with the drive upside down... Regarding changing the position of the disk when I touch it. I have to point here out that the drive reads fine "while" I have my finger on that plastic piece. The plastic piece is just the one that push the disk surface against the head read.


:)

Bryce

The surface of the disk may be fluttering without the assistance of your finger, making it unreadable. Possibly the spring is wearing out and needs to be replaced.

Bryce.

pacomix

Mmmmmmh... that would be weird since that plastic piece is stopped by the metal disk loading plate... Do you know if that is a common problem of this 3" drive units?

pacomix

Hi!


   Today I received a second drive that showed the same behaviour. I replaced of course the belt and cleaned the read head. After putting my finger and reading the disc catalog correctly suddenly started reading all the disks without any problem.
   The other drive still suffers from the problem. The thing is that if I slowdown the motor with my finger by touching the gear under the drive I can load the games without any problem.
   Any clues? It seems that is the drive speed what is causing the problem and I do not want to try a realign by myself... Probably that will cause more problems. Is it possible to modify the drive speed easily?


Paco


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gerald

#10
Quote from: pacomix on 18:26, 11 June 13
Mmmmmmh... that would be weird since that plastic piece is stopped by the metal disk loading plate... Do you know if that is a common problem of this 3" drive units?

According to the picture you posted just above, the floppy itself may be the problem. The metal shield should be open when the floppy is inserted in the drive. On the picture it looks closed.
You should try an other floppy.

pacomix

Hi!


   No no... The floppy is fine. Its metal shield is completely open and it reads the disk when I slowdown the gear of the motor with my magic finger. :)

Bryce

Have you tried other disks in the drive. It would be extremely strange if two random drives both display a previously unknown issue.

Bryce.

pacomix

Yep... They all show the same result... In one of the spanish forum a guy pointed me out that even I slowdown the gear of the motor and I hear the motor slowing down that doesn't necessarily means that the belt is not slipping when it goes full speed. He told me that it might  be that at full speed the belt slips and when I slowdown slightly the motor the belt again gets on track...
Couldn't check that yesterday but I will do that today deep cleaning the gears of the drive.


Paco

pacomix

At the end I have completely fixed one of them by slowing down the motor with the little screw that is over it. But the other drive still can not do a simple cat... :(

pacomix

Of course if I slow the motor down by touching the copper pulley it starts working fine. Could it be that the motor is not working 100% properly?

Bryce

It would be very strange for a motor to get faster when it was broken. Are you sure the pully on the motor doesn't have a layer of gunk still on it? That would cause the belt to be turning faster than it should.

Bryce.

pacomix

Nope... absolutely sure... Today I got a multimeter so I will start measuring the circuit board...

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