- Photo of my Corei64 CMD reproduction FD4000 newly upgraded from Sony mechanisms to a TEAC mech with black face plate. -- photo by AmigaLove
The new drives use beige Sony mechanisms while the original CMD FD4000 drives used (also usually beige) TEAC mechs. One of the main differences with the Sony drive mechs is that they require drilling holes into physical HD floppy disks so that the ED sensors think they are ED disks. This is important if you want to convert HD disks from 1.6 to a stunning 3.2MB.
However, the original TEAC 235J drives from the 90s are “hole agnostic” in that you can keep your power drill in the garage where it belongs. Of course, finding the correct TEAC drive replacement isn’t easy (nor cheap) in 2024 and there are multiple variants to sort through, including the aesthetically pleasing yet pricey black version. As a result, the Sony mechanisms Corei64 supplies with the new drives are a fantastic solution in 2024 to get new CMD FD4K drives into our greedy groping hands. But the promise of the TEAC can make the eyes wander…
Site member CommodoreSam and I went on a bit of a journey (and by that I mean he did the driving and I went along for the ride mashing buttons on the radio). The goal was to find the legendary TEAC drive. Taking things a step further we also wanted to find a variant with a black face plate. And, of course, we wanted to get it all working and confirm the results to the community. Why? Because drilling holes is extra work, plus the drives they look so much cooler with a black-on-black color scheme!
After a bit of research CommodoreSam located some potential TEAC candidates to use in the experiment so we both gambled and snapped up a few. After even more research and experimentation, CommodoreSam got the TEAC drives to work as they once did back in the 90s when CMD sold them new.
The following is CommodoreSam’s guide and photos he took to document the entire process of updating a brand new CMD FD4000 with a TEAC drive. Posted with permission.
—AL
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Special Note: the following change can be done to a new Corei64 FD-4000 reproduction or, as in this case, an original CMD FD-2000 that was also converted to an FD-4000. No original CMD product was harmed and these changes are totally reversible. CMD used the same board for both drives.
Upgrading an FD-2000 to a 4000
To change the FD-2000 to be FD-4000 compatible (but still require drilling holes in disks), the following modifications were previously done.
- The original Teac 1.44mb driver mechanism was replaced for a Sony 2.88mb drive mechanism.
- Jumpers on the main FD-2000 circuit board were moved to match FD-4000.
- Three internal chips were changed with versions used in a FD-4000
- The 1.44mb floppy controller chip was removed from its small socket and a larger 2.88mb floppy controller chip was place in the large socket.
- The 65c02 2 megahertz processor was replaced by a 4 megahertz version.
- The FD-2000 ROM was replaced with a FD-4000 ROM purchased from Corei64.com with RTC board.
- Original new CMD FD4000 with Sony drive, and TEAC replacement in a static bag. Photo by CommodoreSam
Upgrading the CMD FD-2000/FD-4000 Disk Drive from Sony MD-F40W-15 to Teac 235J-5670 drive mechanism
Parts:
- CMD FD-4000 with Sony drive mechanism or similar
- Teac 235J drive mechanism - There are several variations of this drive. We are documenting the Teac 235J-5670 as found coupled with a SCSI board FC-1 board. These together are also known with the model number of Teac FD-235JS-806. If you have a Teac 235J-3631 the jumpers are different, and soldered resistors may not need to be moved.
- Soldering tools (iron, solder, solder wick, flux, etc)
- Pliers or tweezers to move jumpers
- Screwdrivers and Allen wrench set (screws may vary)
- Utility knife or other cutting tool
- White lithium grease and q-tip for application of grease
- Closeup of the TEAC mechanism's label. Photo by CommodoreSam
Step 1
Remove SCSI board from the drive mechanism. This is held on by 4 hex screws and also warranty labels will need to be cut. Unplug ribbon cable connecting the SCSI board to the drive mechanism.
- SCSI board removed. Photo by CommodoreSam
Step 2
Remove mechanism cover and lubricate head rails and screw. Make sure warranty label is cut if not previously removed. Then use a flathead screwdriver or some other pry tool to pry open the cover to get to the internal drive head area. Spray lubricant (e.g. WD-40 lithium grease) on a q-tip and grease the head screw on one side of the head assembly and the straight rail on the other side of the head. Do not spray as you might get some on the head itself. Only a thin layer is needed as the head movement will later spread it the length of the rails. Put the cover back on.
- Photo by CommodoreSam
- Greasing the screw. Photo by CommodoreSam
Step 3
Move resistor from S2 by desoldering it and resoldering it to S1. This is probably the hardest part. Good lighting and a hands-free magnifier is needed for this. The resistor is small and can easily be lost. See videos for good surface mount soldering tutorials.
- Note the location... Photo by CommodoreSam
- Before, After. Photo by CommodoreSam
Step 4
Adjust jumpers to match picture (see below). These specify DS0 and ignores the sensors for HD and ED holes. Please note that this makes it easier to format disks to greater than originally intended density without modification of disks by drilling holes and covering others. This is a great timesaver for personal disks, however disks without the proper holes will confuse other drives expecting these. So sharing may be more difficult. Pictures below are before and after, respectively.
- Before. Photo by CommodoreSam
- After. Photo by CommodoreSam
Step 5
Install the mechanism in the drive housing, removing the previous drive mechanism and replacing it with the Teac 235J. Be sure when you remove the old drive mechanism to note the red strips/colors of the connectors so that you get them back the same. Take a picture! Remove the 4 bottom screws holding the case together, remove the 4 screws holding the drive mechanism in, remove the ribbon cable and power cables from the old drive. Put the Teac mechanism in the same way. Connect ribbon cable and power cable. Then screw drive mechanism back on and put case back together.
- Putting her back together. Photo by CommodoreSam
Step 6
Clean the heads and then test. All these old drives, even the sealed old stock drives, tend to have heads that are dirty with old lubricants or other contaminants from the factory that have aged. I recommend cleaning them for at least 5 cycles with a head cleaner using IPA before putting any disk in. It will ruin disks otherwise and certainly will not read/write properly. Haven’t found a good one out of the sealed bags as of yet without a thorough cleaning.
- Don't skip this step. Even sealed NOS in a bag, it will need it!
Once done, grab a 1.44/1.6 HD floppy disk and fire up CMD’s FD Tools. Now let the (non-drilled) ED disk formatting and partitioning fun begin!
And do it in style!
- Photo by AmigaLove
