Mac 512k floppy drive clicking

[td75]

I have recently acquired a Mac 512k with SONY OA-D34V-22 floppy drive. I have opened the drive up and found the head has moved to the very front and seems to want to keep moving and therefore making a clicking noise. What should stop the head from moving when it reaches it's limit? Could this possible be a faulty sensor or PCB? The limit switch at the back of the drive is engaged. I have cleaned the drive up but still the problem persists. Not sure how these drives work so any help would really be appreciated thanks

 

[Macdrone]

I would bet incorrect floppy cable or drive. Either will cause constant action by the drive. Look up uniserver a post on the floppy cables.

 

[techknight]

Do these drives have head positioning sensors for the home? I cant remember.

 

[uniserver]

like macdrone said i have only had floppy drive do that when i was using an 800k drive in a 128/512/Plus and was not using the floppy cable with the yellow stripe.

The only other situation where i had clicking is, a 512k that had metal covers over the rom's erase hole, somehow they became disconnected during shipment and was stuck on the magnet in the floppy drive, and with a disk inserted it would go CLICK CLICK CLICK.

 

[RickNel]

@technight

Do these drives have head positioning sensors for the home?

Yes - it's an optical sensor that is very precise because on any reset or disk insert it sets the baseline for track 0 alignment. If that sensor is dirty or not reading for some reason, the head servo may keep seeking Track 0. It is fixed with one screw. If that was loosened or has been moved, you can have a lot of trouble trying to restore head alignment. It might be worth checking that the 3-wire connector to that sensor has not been damaged, it is quite exposed to any knock while handling the disk unit.

Rick

 

[snuci]

Yes - it's an optical sensor that is very precise because on any reset or disk insert it sets the baseline for track 0 alignment. If that sensor is dirty or not reading for some reason, the head servo may keep seeking Track 0. It is fixed with one screw. If that was loosened or has been moved, you can have a lot of trouble trying to restore head alignment. It might be worth checking that the 3-wire connector to that sensor has not been damaged, it is quite exposed to any knock while handling the disk unit.

I've fixed a drive like this by just cleaning out the "C" shaped sensor with a Q-tip.

 

[techknight]

@technight

Do these drives have head positioning sensors for the home?

Yes - it's an optical sensor that is very precise because on any reset or disk insert it sets the baseline for track 0 alignment. If that sensor is dirty or not reading for some reason, the head servo may keep seeking Track 0. It is fixed with one screw. If that was loosened or has been moved, you can have a lot of trouble trying to restore head alignment. It might be worth checking that the 3-wire connector to that sensor has not been damaged, it is quite exposed to any knock while handling the disk unit.

Rick

thaaats what i thought. ;-)

 

[td75]

Thanks for all the help everyone. I don't think it's a cable fault as it was working before and cable hasn't been changed. I think it may have something to do with sensors so will clean these up as soon as I get some time to test again.

 

[td75]

Finally found faulty part.. it was a faulty sensor after all. I ended up swapping a sensor from a working drive and works perfectly. Have cleaned the other sensor and resoldered connections and cleaned the plug but still doesn't work. Have tried testing with multimeter but not too sure what I'm testing for. Anyone know where I could find replacement sensor for this? Part number on sensor itself is 1110 47 and on the sensor PCB is 1-605-399-11. Also what is the easiest way to realign this sensor or it is just trial and error?

 

[techknight]

I had a feeling it was a sensor I knew it by how is acting. What you need to do now is replace the LED that's inside the optical photo interrupter block. this led should be a standard off the shelf infrared

 

[td75]

I had a feeling it was a sensor I knew it by how is acting. What you need to do now is replace the LED that's inside the optical photo interrupter block. this led should be a standard off the shelf infrared

Thanks for your help. The LED seems to be glued solid into the block, not sure how to get them out without breaking the block itself..

 

[uniserver]

I am sure i have at-least 3 or 4 or those that are good.

in Mi, usa. but sounds more like you are having fun repairing the old one… witch i think is pretty cool.

another crude way maybe is to drill it out? slide the new IR led in there…

and black epoxy it in?

 

[td75]

Ha ha! Yeah would be fun if I could get them working! That is an idea to drill them out but will probably end up butchering the block!

I now have 2 non-working drives.. the one with a good sensor gives a "X" on floppy and keeps ejecting the disk no matter were I move the sensor. I did mark it when I removed it so not sure what has gone wrong.

 

[td75]

Got the one drive to read disks again... had to adjust the head on "x" axis slightly - one to go Uniserver if you have a spare sensor block to sell please let me know.. thanks

 

[techknight]

Those are off-the-shelf opto-interrupter modules. if the LED is molded, you can buy just a replacement 4 pin module on digikey or even ebay. cheap.

Reason i know the LEDs go bad, the front-load whirlpool washers have a locking actuator that fails. VERY often. and its the LED that fails in the opto-interruptor.

 

[td75]

Those are off-the-shelf opto-interrupter modules. if the LED is molded, you can buy just a replacement 4 pin module on digikey or even ebay. cheap.
Reason i know the LEDs go bad, the front-load whirlpool washers have a locking actuator that fails. VERY often. and its the LED that fails in the opto-interruptor.

Thanks for your help. Have done searches and found similar modules but they vary quite bit in size. Can't seem to find anything with same dimensions. This is the closest I can find here on eBay so not sure it will be compatible?

http://www.ebay.co.uk/itm/KTIR0121DS-Slotted-Infra-Red-Photo-Interrupter-Opto-Switch-Sensor-PH03-/400498159249?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d3f8cee91

 

[techknight]

doesnt matter, as long as the interrupter blade fits between the gap.

 

[td75]

Okay thanks have bought one from eBay hopefully it works!