Author Topic: 6128 disk drive issue  (Read 6948 times)

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Offline Morn

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6128 disk drive issue
« on: 21:18, 10 July 10 »
Hi!

I've replaced the drive belt on my 6128 and the disk spins up OK, but it looks like the read/write head doesn't move. It just makes a buzzing noise when you do e.g. a "cat" with a disk in the drive:


http://www.youtube.com/watch?v=DX1DN0Jaz0Q

So, is the motor broken? But then why does it hum like that?

I can move the read/write head by hand by turning the metal rod on the right, so there doesn't seem to be anything in the way.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline MacDeath

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Re: 6128 disk drive issue
« Reply #1 on: 05:54, 11 July 10 »
Sometimes the head get blocked by the "endless screw"..
So just "turn" this endless screw so the Head is no more blocked on max.

Of course this can not be that, but I had such case...(and actually had to re-open my amstrad, removeing again a lot of screw...)

OMG the head move no more ? well the endless screw ("vis sans fin" in french) has gone on max in one of direction so it is blocked... er... Jamed...'(bump up the jam!)

Just get it a bit back with your hands (fingers, dick, whatever)... by turning on its axis the endless-screw (which actually has an end...lol...)
May work in a lot of case.

Testing a disk drive with no Belt can drive to this, as the head reach the end of its screw reach because the disk can't turn... so it search a lot... (sort of)
and when a screw is turned to the max, it jams itself...

Hope this is it, as screw concept is hard for me to explain in english... we all know love language (screwing tongue) is french... lol... ;D

Hope this is only it.


Needless to say, you must "open" your Amstrad so your finger (or dick or whatever) can access to this "endless screw"... :P


Principle of the endless screw :


just replace the clockwork wheel with the head of the driver... ::)
As the reading/writing head is translation based instead of rotating...well the endless screw actually has an end then...lol...


Ouch, my sexual life is so pathetic... :laugh:
 
« Last Edit: 06:12, 11 July 10 by MacDeath »

Offline Morn

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Re: 6128 disk drive issue
« Reply #2 on: 15:29, 11 July 10 »
Thanks, MacDeath!

However, I can turn the "endless screw" (by which I assume you mean that thingy sticking out of the stepper motor) all the way by hand. Are you sure this can be the problem then, if I can move the r/w head all the way forward and back manually?

But I'll look into this possibility.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Devilmarkus

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Re: 6128 disk drive issue
« Reply #3 on: 17:05, 11 July 10 »
Mal eben auf Deutsch:
Sieht so aus, als ob der Greifer, der auf der Schnecke sitzt, defekt ist.
Dort ist normalerweise ein kleiner Metallstift drin, welcher in die Windung rastet.
Schau mal nach, ob der nicht richtig fasst oder eventuell gänzlich fehlt.

Eventuell sind auch die Kopf-Führungsachsen nicht mehr richtig festgeschraubt?
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Offline Morn

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Re: 6128 disk drive issue
« Reply #4 on: 17:44, 11 July 10 »
Wenn ich die Schnecke von Hand drehe (direkt vor dem Motor is da so eine Art Stift an der Achse, mit dem man die Achse leicht drehen kann), bewegt sich ja der Kopf wunderbar hin und her wie er soll. Die Führungsachse ist auch fest. (Oder gibt es mehrere?)

Nach dem was in Wikipedia steht denke ich dass der Schrittmotor in beide Richtungen unbeschränkt drehbar sein sollte; also denke ich mal dass MacDeaths Idee dass das Gewinde "am Ende" angelangt ist nicht sein kann.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Devilmarkus

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Re: 6128 disk drive issue
« Reply #5 on: 19:50, 11 July 10 »
Lässt sich der Kopf auch bewegen, ohne dass Du die Schnecke drehst? (Versuch mal, wenn er vor und zurück zu schieben ist, ist etwas kaputt)
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Offline Morn

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Re: 6128 disk drive issue
« Reply #6 on: 20:52, 11 July 10 »
Nein, da bewegt er sich nicht.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Devilmarkus

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Re: 6128 disk drive issue
« Reply #7 on: 20:54, 11 July 10 »
Please post a HIGH detailled photo (and sharp) of the stepper motor + the head-slider.
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Offline Morn

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Re: 6128 disk drive issue
« Reply #8 on: 02:01, 12 July 10 »
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Devilmarkus

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Re: 6128 disk drive issue
« Reply #9 on: 09:08, 12 July 10 »
Humm ok.
It looks like an electronic component is bad.
Maybe an IC or a transistor.
Hard to guess.
Need to see the real hardware.

I am also not sure (actually I don't have this drive type here) if there's a plastic ring missing around the "metal nose"

Perhaps also a cable is missing as marked in the image above but I am not sure, too, here.
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Offline Bryce

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Re: 6128 disk drive issue
« Reply #10 on: 11:52, 12 July 10 »
I also don't know this particular drive, but most drives have a switch or sensor to let the electronics know that it has reached the end position. If this is broken the motor will try to keep turning even when it reaches the end. Is there such a switch visible in the drive? If so, you should check that it's switching correctly.

Bryce.

Offline Devilmarkus

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Re: 6128 disk drive issue
« Reply #11 on: 16:32, 12 July 10 »
While I was sending a PM I looked closer to the video on youtube.
Did you connect the 12v power plug?
I cannot see this.
Make sure the CPC also has 12v connected.
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Offline arnoldemu

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Re: 6128 disk drive issue
« Reply #12 on: 16:39, 12 July 10 »
Hi!

I've replaced the drive belt on my 6128 and the disk spins up OK, but it looks like the read/write head doesn't move. It just makes a buzzing noise when you do e.g. a "cat" with a disk in the drive:


http://www.youtube.com/watch?v=DX1DN0Jaz0Q

So, is the motor broken? But then why does it hum like that?

I can move the read/write head by hand by turning the metal rod on the right, so there doesn't seem to be anything in the way.

Martin
Does the CPC eventually give a error message?
Does the red light go on/off on the drive like the cpc is trying to read?

It seems that the drive is trying to step to the next track but the head is not moving. The CPC then tries to read the disc and verify the location of the head, and then performs it's normal error retry process.

The basic retry process is that it will seek to drive 0, then to the track and try a read. If this fails it seeks to track 39, then back to the track to try again. it repeats this over and over and over and eventually gives up.

So, it's like the stepper is not engaging and moving the head. almost like the stepper is dead, or not enough power.

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Offline Morn

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Re: 6128 disk drive issue
« Reply #13 on: 18:37, 12 July 10 »
12 V is connected, but maybe I should measure output from the monitor to make sure the voltage is as it should be...

I'll also check out what the LED is doing.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Morn

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Re: 6128 disk drive issue
« Reply #14 on: 18:48, 12 July 10 »
So, the LED is always dimly lit, even when there's no disk in the drive. I don't remember if that's normal for the CPC or not.

When I enter "cat", the disk drive spins up, then the head starts humming, the LED flickers a little (sometimes it's brighter and sometimes darker than average).

After perhaps 15 seconds or so the command terminates with "Bad Command"! Not the usual read error, retry, ignore, cancel.

Martin

P.S. I've also measured the monitor 12 V source with a multimeter, it's 12 V all right.
« Last Edit: 20:26, 12 July 10 by Morn »
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Offline MacDeath

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Re: 6128 disk drive issue
« Reply #15 on: 19:57, 12 July 10 »
Well from what i told, it is probably not that, but I had such case...
Disk error missing because no Belt...
change the belt : still don't work...
I simply turned a "little bit" the endlessscrew "back"...and it worked again.

Just is, no need to turn it completly bach and forward.
Just to "unblock" the jamed mechanism...


That's all.

Also Bitte... try to translate your Deutsch...Google translator is somewhat...not that efficient...

Offline Morn

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Re: 6128 disk drive issue
« Reply #16 on: 20:25, 12 July 10 »
Well from what i told, it is probably not that, but I had such case...
Disk error missing because no Belt...
change the belt : still don't work...
I simply turned a "little bit" the endlessscrew "back"...and it worked again.

Just is, no need to turn it completly bach and forward.
Just to "unblock" the jamed mechanism...

So do you mean: move the screw back and forth a bit with the r/w head attached to it or move the r/w head out of the way first?

Quote from: MacDeath link=topic=1114.msg11091#msg11091   date=1278953849
Also Bitte... try to   translate your Deutsch...Google translator is somewhat...not that   efficient...

Sorry for that. Of course it was Markus who introduced German into this thread. How devilish of him!   :)

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Gryzor

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Re: 6128 disk drive issue
« Reply #17 on: 10:17, 13 July 10 »
Btw, I do think that the led is dimly lit when the drive is idle...

Offline Bryce

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Re: 6128 disk drive issue
« Reply #18 on: 12:36, 13 July 10 »
Yeah, the LED should always be a little bit lit, even with no disk in the drive.

After reading through the posts again, I'm not sure we've really understood the problem. So here's some questions:

Does the disk spin when the buzzing sound can be heard?

Has the drive head ever moved?

Does the "endless screw" turn but the head stays in the same place?

At the moment, I really think the "endless screw" is just jammed, it should be covered in grease, so that the head can smoothly slide along it's threads, but this has probably dried up over the years. I'd suggest putting some Vaseline or similar grease on the "endless screw" and then manually turning the screw until the head has travelled the full distance of the screw to make sure it's properly spread. Then try the drive again.

Bryce.

B.t.w. the real name for the "endless screw" is a worm drive.

Offline Morn

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Re: 6128 disk drive issue
« Reply #19 on: 13:07, 13 July 10 »
Does the disk spin when the buzzing sound can be heard?

Yes. You can hear the disk spinning up in the video. And I also wrote in the first post, "the disk spins up OK".

Has the drive head ever moved?

Not visibly and great distance, but obviously since it's buzzing, it does move back and forth a little bit to create the sound.

Does the "endless screw" turn but the head stays in the same place?

No, when I turn the worm drive screw by hand, the head moves as it should. And it moves easily (as I wrote in the FP, "I can move the read/write head by hand by turning the metal rod on the right").

The mechanics seem to be fine, but somehow the motor doesn't work. FP: "So, is the motor broken?" Of course I could try a little more oil, I suppose it can't hurt.

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline arnoldemu

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Re: 6128 disk drive issue
« Reply #20 on: 13:17, 13 July 10 »
It definitely seems that the worm drive is broken because you can turn it and the head moves.
Or maybe a bad connection to the worm drive is here causing it to make the head vibrate.
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Offline Bryce

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Re: 6128 disk drive issue
« Reply #21 on: 14:04, 13 July 10 »
Hmmm, ok, if the oil doesn't work, then it's time to remove the motor, dis-mantle it and see why it's not turning as it should :( Fiddly job, and if anything mechanical is broken, then I doubt it will be repairable. Time to look for a new motor perhaps.

Bryce.

Offline Morn

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Re: 6128 disk drive issue
« Reply #22 on: 21:08, 13 July 10 »
Markus has kindly offered me to send him the drive so he can try to repair it. I think that's what I'll do, because my impression is that it's either the motor blocking somehow or the stepper motor controller malfunctioning. Either way, a replacement part is probably necessary.

But first of all I'll drench it all in olive oil and see what happens. If it doesn't do anything else, it will at least make the drive smell delicious.  :)

Martin
Primary computers: CPC 6128 (’87–’90)→Amiga 2000 (’90–’95)→Windows/Linux/FreeBSD PC (’95–’06)→MacBook (’06–'12)→Linux/Windows PC and MacBook ('12-)

Offline Bryce

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Re: 6128 disk drive issue
« Reply #23 on: 21:15, 13 July 10 »
May I suggest the "Extra Virgin Peloponnese from 2008", cold pressed of course. It has a beautiful aroma and it's dark texture will go a treat with the CPCs grey casing.

Bryce.
« Last Edit: 11:44, 14 July 10 by Bryce »

Offline Gryzor

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Re: 6128 disk drive issue
« Reply #24 on: 10:40, 14 July 10 »
Um... While Peloponnese  oil is just great (my girl is from there, we get lots of free olive oil each year, and we're owners of olive fields too!), I'll say it once again - olive oil is really, really bad. Try using it on a door hinge and see the muck that starts building up in a while, then try to envision your electronic equipment in its place...  Also, old olive oil doesn't smell nice, so it's a lose/lose proposition :D

PS Bread with olive oil... mmmmm...