Tech Flashback: iomega ZIP 250 IDE/ATAPI Drive Teardown

It’s interesting what you can find when you walk around on scheduled council clean-up dates. I managed to salvage an iomega ZIP 250 IDE/ATAPI drive from an unwanted computer, only to find that it was no longer functional. It wouldn’t even spin or eject the cartridge, and the ATAPI Identify command hangs.

ZIP 250 Front Face

Oh well, I guess that’s why it was thrown out in the first place! But at least we won’t let it go to waste entirely …


Owners of the ZIP 100 drives will recognize the exterior as being virtually identical – and having taken apart many ZIP 100 drives, I can definitely vouch for the similarity.

Lets pop the cover off …


As we can see, the plastic side rails form the guide for the whole mechanism to slide and engage when a disk is inserted. There is springy inserts on the top cover to keep the disk seated onto the motor plate. The mechanism itself is connected by springs to the bottom plate to return it to the ejected state. The head mechanism and solenoid are under a plastic shield, with the blue lever arm aligned for the emergency eject hole in the rear. The controller board sits at the bottom.

Head Assembly Top

Removing the screws for the top protective plate removes it along with two bar magnets (in orange) which are attached to the metal form – itself adhered to the top cover using adhesive tape. Yes. Sticky tape. The same arrangement is found on the opposite side of the black plastic form – another two orange bar magnets, metal form, and adhesive tape. Anyway, the head is visibly docked in its protective sheath – this is automatically accomplished by the spring in the lower edge of the image and the blue lever which pushes the head voice coil motor right into the rear. The voice coil motor is seen as the red wire coil which goes around the two metal bars labelled 20 and 13. The solenoid can be seen at the top of the picture – this actuates a head unlock mechanism which disables the return spring when the head is ready to be loaded onto the disk – i.e. disk inserted and spinning at the right speed.

DSC_0024Here’s a picture of the head itself. It’s a bit dusty, but it looks virtually like any other head from drives of the era, except for what appears to be a cut in the head – maybe for aerodynamics or field shaping reasons.

ZIP 250 Spindle Motor

Here’s the ZIP 250’s spindle motor. How do you “connect” a disk to the motor without any drive holes? Well, the grey thing is a ring magnet – so the disk hub literally “sticks” to the motor through the use of a magnet.

ZIP 250 Spindle Motor Rear

Looking at the rear of the motor, we can see it’s been made by one of the most major precision motor manufacturers – Nidec. They make a whole heap of spindle motors for hard disks and computer fans as well.

ZIP 250 Controller Board

Here’s the controller board. It appears to have been radically simplified, being a bit “lonely” and smaller than some others I have seen. Part of the reason may be that this is a “later” model drive, and better ASICs have been developed with mask ROM rather than flash. The failure is still a mystery though – nothing obvious has gone wrong.


The heart of this drive is an ASIC named BRUNO – they seem to have a habit of giving their ASICs names! I can’t remember the others though …

Retroreflector Sensor

Here’s a spot of difference between the ZIP 100 and ZIP 250 drives – the use of multiple retroreflector sensors. This is used to sense the capacity of the disk – and may operate at different wavelengths.

Ah well … farewell ZIP 250 drive!

About lui_gough

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4 Responses to Tech Flashback: iomega ZIP 250 IDE/ATAPI Drive Teardown

  1. numeric says:

    I never saw ZIP 750 myself. I always wondered, what is its appearance for optical capacity detection. If ever you get your hands on a ZIP 750 disc, please do share a picture of its corner.

    • lui_gough says:

      I will if I ever do – but to date, I have not handled a 750 myself, as it seems it was never really popular because it came too late and was too slow for many users who had already made their minds up to go with CD-R/RW media. From memory, the ZIP 100 was a transparent plastic retroreflector, with the ZIP 250 disks having a light-banana-yellow plastic piece where the retroreflector was.

      – Gough

      • numeric says:

        From memory, you are correct. So I suspect, in order to be rejected by 100 and 250, a ZIP 750 capacity marked corner might be black. I do not know what Iomega would have done, if ZIP were to go beyond 750Mo capacity, what other simple colour or surface reflectivity could be chosen to be safely handled by older drives.

  2. clearscreen says:


    many many thanks because i’ve found some very old internal ide zip and i would dissasemble it in order to clean it deeply (and believe me it need some cleaning !)

    It will go on my ultimate dos game (celeron 300A, 3DFX 4500, AWE 64, 3″1/2, 5″1/4 and ZIP now 🙂

    Thanks again.

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