Mac 512k - OA-34V22 / Sometimes do not start...with a kick ove the spin it move..why?

[mosaiko]

Hi there!

I've recovered an external M0130 that was in the right time to be cleaned to restart ... after the cleaning process the drive with a SONY 0A-34V 02 work fine reading and writing... but sometimes the spin stop and do not start until i do not move a little bit the central round that stay under the floppy.

Inserting a floppy in the drive, the MAC 512k recognize it.. telling me all the correct message, obviously when happen that the spin-motor do not run the mac ask me to Eject or initialize the floppy... but the spindle motor stay stopped... ONLY moving a little bit the circle (i use a simple Q-tip when the floppy is not over it) .. then it move again...

To prove it leaving the drive connected to the MAC512K without the box and the upside metal mechanism.. and repeating the close of the right light sensor with my finger i replicate the problem... for X times it do everything then the normal start of the spin and then wihtou the floppy the message to eject... at certain time the spin stop and nothing move until i give a little move on the circle with my finger... after this for other Y time all goes fine again...

It is something that i would like to FIX.. any idea ? ...

the electronics under the drive is fine ( i verify capacitors but also substitute the electronics with another one working.. same defect), if something need to be repaired i feel is in the upside ... maybe a capacitor.. or something else.. but i feel is something easy to solve..

i hope to hear some feedback soon

Thank you in advance! ^_^
Michele

 

[MacTech68]

This appears to be a fairly obscure - albeit common - problem with the 400K Sony drives.

The theory is that one of the hall effect sensors in the spindle is faulty. There seems to be no cure for this, other than getting 3 working sensors by using a "donor" drive.

https://groups.google.com/d/msg/lisalist/SNVtJk7zx28/y2AqnKUpNVMJ

The sensors appear to be a HTS-103A (per sony circuit diagram for generic single sided drive), but I don't seem to be able to find any information or cross-reference.

EDIT: Seems the Sony documentation may be in error, and the part is a THS-103A

 

[mosaiko]

This appears to be a fairly obscure - albeit common - problem with the 400K Sony drives.

The theory is that one of the hall effect sensors in the spindle is faulty. There seems to be no cure for this, other than getting 3 working sensors by using a "donor" drive.

https://groups.google.com/d/msg/lisalist/SNVtJk7zx28/y2AqnKUpNVMJ

The sensors appear to be a HTS-103A (per sony circuit diagram for generic single sided drive), but I don't seem to be able to find any information or cross-reference.

EDIT: Seems the Sony documentation may be in error, and the part is a THS-103A

Yes it is something that involve the movement of the spindle motor... so interesting to look at a right substitute for these hall effect sensor, i misunderstand these sensor.. now i see :

http://en.wikipedia.org/wiki/Hall_effect_sensor

... so have you checked the code HTS-103A onboard ? ... i do not found characteristics for it...

If someone has the electric scheme of the OA-34V 02 or similar... maybe i can understand something before i start desoldering the upside or control the pins..

 

[MacTech68]

...If someone has the electric scheme of the OA-34V 02 or similar... maybe i can understand something before i start desoldering the upside

I haven't found any data other than a short-form listing (which may be incorrect) which states: "Ga-As 10mA 450ohm - 900ohm".

As for the circuit, the best I've seen so far is this, but I'm not sure how closely it matches those in the Macs.

 

[mosaiko]

I haven't found any data other than a short-form listing (which may be incorrect) which states: "Ga-As 10mA 450ohm - 900ohm".

As for the circuit, the best I've seen so far is this, but I'm not sure how closely it matches those in the Macs.

Nice , so i start desoldering next days the upside of the drive and i take some pictures of it and steps to share for everyone that can be interested on this possible repair.
In the meantime i recover from by garage another drive i leave there for spare... but i would like to understand in deep this problem and see if we can found in the market some spare for Hall factor sensor that can replace the dead ones... i found more hall sensor all around but i need to understand well the right characteristics of a "possible" substitute... voltage, ampere...

by the way; the potential substitute need to be identity as Liner, unilinear or bipolar
http://www.nskelectronics.in/hall_effect_sensor.html

let's see..

 

[MacTech68]

According to Allegro Microsystems, the Toshiba THS102 was equivalent to a UGN3605K - but even THAT was discontinued in 1991.

It seems that Toshiba made 3 case styles for each type. IE:

THS121 = "type 1" case SMQ
THS122 = "type 1" case USH
THS123 = "type 1" case S-SIP

So I'm assuming that THS102 is the same as a THS103, but in a different case style.

EDIT: I've managed to find what appears to be a TOSHIBA chart which states the THS119 is a suitable replacement for the THS103A and certainly the THS119 is a 4pin SIP package.

Data Sheet for THS119:
http://exp.as2.yamanashi.ac.jp/openlab/apparatus/manual/THS119.pdf

 

[mosaiko]

.. some pictures over the unmount motor part; visible the H1 in the first picture and the 3 position of the 4 pin hall sensor in the second picture .. i'll desolder them next week end. The metal cup comes out easily desoldering from the back the 3 pin connector of the flat and opening with a little flat screwdriver the 3 hooks.

I controlled all the electronics and the other components like little electrolitics capacitors by 1uF are in perfect conditions.

 

[MacTech68]

So have you sourced a replacement?

I'll be interested to see how this turns out.

 

[mosaiko]

So have you sourced a replacement?

I'll be interested to see how this turns out.

i try first to understand if some little write was over the sensor....

but nothing was there.. i've found a local place where probably they can have some spare... next days i go there to look for these hall sensor; if i can identify them and/or have a good substitute then i advise with codes and technical spec..

 

[mosaiko]

EDIT: I've managed to find what appears to be a TOSHIBA chart which states the THS119 is a suitable replacement for the THS103A and certainly the THS119 is a 4pin SIP package.

Data Sheet for THS119:
http://exp.as2.yamanashi.ac.jp/openlab/apparatus/manual/THS119.pdf

Yes, i found the same spare part and i think that it has all the characteristics needed... i try to identify the actual Hall sensor characteristics.. that is a SONY one... for what i get out online, these old Hall sensors where compatible between SONY, TOSHIBA and SANYO; an interesting reference is in here :

http://www.palsite.com/pcat_hmotor.html

in it is recommended the glue remove (not present in the AO-34V-02 SONY case) and control possible dry solder joints or electrolytic capacitors dryed up; after this control, the substitution is needed for a common fault of these hall sensors.

ADD. I found this TOSHIBA table of discontinued ID codes and the THS103A and THS104 are bonded to THS119. Seems that the TOSHIBA Ga-As Hall sensor "THS100 series" is what we need.

http://wenku.baidu.com/view/81a8498fcc22bcd126ff0c47

 

[mosaiko]

.. i found a source for the THS103A-H ; it will take some times for the delivery to my address but is not urgent the repair ;-); the use of THS119 is same as this sensor; asap i receive the spares units i'll start one by one the substitution and try to found the broken one

The hypothesis if for the H1 that i unmount like first; le's see

 

[MacTech68]

Keeping my fingers crossed.

 

[mosaiko]

.. ok time to start ... spare parts are arrived ^_^ ( i've a good qty in stock now) :

I start one by one to identify the broken sensor.. first will be unmounted H1 .. ;-)

My idea is to see f we can found a value to measure to identify the broken one easily

 

[mosaiko]

Yes.. the sensor was the problems.. not 1 but at last 2 of them was to be changed.. in particular H2 and H3 .. H1 was the only one 100% working.. and i wrongly thought immediately he was the guilty .. anyway.. following some pictures where are visible the steps.. to substitute the H2 i desolder also another connector.. but the operation is been easy... Important to underline how these sensors can be damaged by the heat.. so when soldering is needed to be fast ^_^

so, the spare parts i use are been perfect to be used and compliant 100%.. If someone in need an help to physically repair same problem, contact me and if you want i can also do the same in your broken part... or send you the needed sensors..

I take also a couple of short video, after H2 exchange ..and to register the fact that when only one sensor (H3) was steel broken.. the effect was that the spin run and move always you insert the floppy but the first time ONLY you get the spin doing the right movement to load it..the second time in the most cases.. the spin run doing only a shorter spin not useful to make the drive read the floppy...

Differently with two sensor like was my case the spin run certain time yes and other not, based on where is the the position of the magnets.

Obviosuly when all the 3 sesons are broken.. nothing move...


Maybe i can publish also these video... but are not so important... i think this is enough ^_^

problem solved!
Mik

 

[MacTech68]

That's great, and finally, proof of a theory.

Thanks for the pics and the efforts to follow up on this repair.

 

[mosaiko]

That's great, and finally, proof of a theory.

YEs right.. it confirm

 

[mosaiko]

Like last reply... and probably to open another Thread dedicated... I'm checking to repair now also some lesser old classic Macintosh Floppy drives.. in particular is the Superdrive MFD-75W and similar. release.. I notice immediately in these drive a couple of problem... one easy to solve ( the eject mechanism that go out of work normally for a crecked gear that i'm rebuilding in series ;-); and that destroy itself because the drive go too dirty and became immobilized by the old grease and long time stop ).. and a second problem that is pretty common and that is again.. Spin motor do not turn when floppy is inserted in... hmmm... I'll disassembly one of this drive.. and lets see if someone else here have some experience or info and feedback over this issue too..

Some components or bad contact can be damaged... and again the spin is controlled by Hall sensor as well and an Hall Index.. this time are SMD components easy to have access from the bottom of the drive.

 

[MacTech68]

The problem with the second model 75W is probably one of the micro-switches at the front edge of the drive.

This thread might also be helpful:

https://forums.macrumors.com/threads/1354182/

 

[mosaiko]

Yes you are right, the Switch that close the circuit to let the spin motor start when the floppy is inserted is on the the right side looking the insertion hole; i see two version of drive with two different switch-button on the right, one version is with a single switch and another in "the older drives" there are two separated momentary-switch, the on with the shorter white button is the one to check. If all work fine, pressing it the spin motor start... but not in this drive case i'm looking to repair ; the switch work fine and is not broken or dirty; i tested its functionality on/off with the multimeter over the two soldered point.. and it works.

Nice post liked, It confirm a typical cracked double gear... for it i'm preparing some spare parts for the yellow double gear that is not a standard one.

(this drive is been an hard cake!.. poor gear no more teeth ^_^)

I disassembly the floppy drive completely; and now i try to control all the components; every suggestion is welcome.. like Hall sensor in this version there are 3 SMD marked on top 120 with 4 legs :

Visible are in here the 3 hall sensors (H1,H2,H3) and the Index Hall. the 120 is probably indicating the value 120mA. .. looking now an easy test over these sensor... ^_^

 

[MacTech68]

Not so sure about this one. The microswitches with the white tubular post have been intermittent in many drives I've repaired.

You could test that by soldering a bridge across the switch to see if it makes the drive run.

I'll look in my library and see if I have a circuit for this one, but you may be able to find a Sony technical data sheet for the controller IC.

 

[mosaiko]

Not so sure about this one. The microswitches with the white tubular post have been intermittent in many drives I've repaired.

You could test that by soldering a bridge across the switch to see if it makes the drive run.

I'll look in my library and see if I have a circuit for this one, but you may be able to find a Sony technical data sheet for the controller IC.

.. ok.. so i'll try to bridge the switch and i let you know... about the SONY Tech data sheet.. i'm looking for.. if you found something .. is always welcome

 

[mosaiko]

unfortunately i try to do the bridge in the right first microswitch that control the run of the spin motor but it do not give any movement of the spin... i'm continuing checking components .. but all seems to be ok.. not jet controlled are these hall sensors.. now i see better the write over these seonsor.. and is I 20 ... that stay for Imput current max 20 mA ^_^ ... i'm looking anyway some spare of these sensors.. I think to have identify, if will be needed.. the possible spare parts :

http://www.cy-sensors.com/CYTY-InSb.pdf

To choose the right one (InSb Hall Effect Elements), is needed to understand the output voltage range... that I think need to be the correct one.. CYTY211 i feel could be the right one

.. I'm thinking to solder a thin wire to the output of the sensors ( pin 3 seems to be it.. but i also need to identify it)... and connect it to the multimeter with the ground.. and measure the voltage connecting the drive and moving the circle with a finger... can be a good idea.. or not ?

 

[MacTech68]

It could help to see if they're functional.

I've tried looking for a circuit for these (or even the PC Floppy equivalent) and have come up with nothing.

I can't even find data for the controller which, if I'm correct, is a Sony CX20174.

I'm looking at the 3 low profile electrolytic capacitors on the front edge of the drive. I know that sometimes in old VCRs that these can be a point of failure. But, I don't know if they are actually involved in the servo control or not.

 

[mosaiko]

... back from some time, cause i've not found the time to go on these drives... first of all i rebuild the little plastics Gear of the floppy motor.. now i can reproduce these gear as many as needed.. ;-)

.. for electronics i now come back on it; i've a drive now that work.. so that i can even do comparisons on the two drive.

YEs the controller is rightly identified as Sony CX20174;

If any new idea are arrived.. i'll continue now on the sensors and controller.. ^_^

 

[maczo]

I'm also trying to fix a 400K drive that has a motor problem. It can write disks, but such disks cannot then be read by other drives. Also, disks wrote by other drives cannot be read by this faulty unit. Do you guys think that this problem can be related to the Hall sensors or to the controller itself? Other components on the motor board appear to be fine. If I swap the motor board with another motor board from a working drive, then the unit works fine with the known good floppies.

I also have a question for mosaiko. I'm trying to repair the broken gears from 800K floppy drives too.
Can you give me a hint on how to do that? I tried doing a rubber mold and resin cast, but the final part was full of little bubbles and broke easily.
Can you give me directions, or can you sell me your replicas? Thank you.