Tandy 1500HD/2810/3810HD Laptop 26-Pin FPC Floppy Drive Ribbon Cable

[Paralel]

Does anyone know if the 26 connector FPC floppy drive ribbon cable pinout for the Tandy 1500HD/2810/3810HD laptops is known? Or if it is a common standard?

I've come across a number of 34-pin + floppy power connector to 26 connector FPC floppy drive cable adapters and want to find out if that would allow me to adapt a 34-pin servo type floppy to use with the 1500HD I have.

The floppy drive in question is a Matsushita EME-263MG. The 26 connector FPC cable is permanently attached to the drive (seems kinda like a stupid design given how prone FPC cable are to various problems...). I searched quite a bit but came up with practically nothing about the drive or its pinout.

Any info is appreciated.

 

[Juror22]

I imagine the connector and pinout is similar to the one used in the Tandy 1100/1110HD which is documented (I made a couple of home-made adapters for those models a few years back, before I became better at fixing the original drives). I've seen and wondered about those adapters you are referencing, but I've not had time yet to determine if a) the pinout is the same in the floppy drives used in the 1500HD (and their Panasonic cousins) or b) if the adapters would work.

If I get to it first I will let you know, but if you or someone else finds out, it would help if they posted back as well.

 

[Paralel]

I imagine the connector and pinout is similar to the one used in the Tandy 1100/1110HD which is documented (I made a couple of home-made adapters for those models a few years back, before I became better at fixing the original drives). I've seen and wondered about those adapters you are referencing, but I've not had time yet to determine if a) the pinout is the same in the floppy drives used in the 1500HD (and their Panasonic cousins) or b) if the adapters would work.

If I get to it first I will let you know, but if you or someone else finds out, it would help if they posted back as well.

Well, I ordered one, so I'll report back with my experience once it gets here.

 

[Paralel]

To follow up on this, the 34 pin to 26 conductor FFC adapters have the 26 pin interface upside down compared to the Matsushita (Panasonic) drives in the Tandy laptops, as a result the pinout is reversed. As such, you need to use a "reverse" FFC cable to interface between the adapter and the Tandy laptop floppy controller. A "reverse" FFC cable has the conductor interfaces on each end of the cable on opposite sides. Here is an image for anyone that is having a hard time picturing that:



Of course, as far as I know, no one has ever created a reverse FFC 1.25 mm to 1.00 mm cable. There is a forward FFC 1.25 mm to 1.00 mm cable that can be purchased, but you would have the end of the FFC cable interfacing with the floppy adapter in reverse. You could still use it, but you'd need to use an FFC extension board with a second reverse cable in order to swap the direction of the conductors on the FFC cable to match the pinout of the floppy adapter.

 

[Juror22]

That is unfortunate. Perhaps the adapter was engineered to work with the synthesizers that use similar Matsushita drives (and seem to provide more business in this area) and that is why they are "reversed", and don't quite work, out of the box (just a guess).

 

[Paralel]

I have been able to determine the "pinout" of the 26 connector interface for the Matsushita EME-26x series of floppy drives, which is also the corresponding pinout for the 1800HD, 2810HD, 2820HD, 3800HD, 3810HD, 3820HD floppy interface. It is the following:

  1   +5 Vdc          14  Step
  2   Index           15  GND
  3   +5 Vdc          16  Write Data
  4   Drive Select    17  GND
  5   +5 Vdc          18  Write Gate
  6   Disk Change     19  GND
  7   +5 Vdc          20  Track 00
  8   NC              21  GND
  9   NC              22  Write Protect
  10  Motor On        23  GND
  11  Mode Select     24  Read Data
  12  Direction       25  GND
  13  GND             26  Side Select

Fortunately for us, it follows a generally accepted pinout for floppy drives that use a 26 connector FFC/FPC. That one exception is that the 7th connector on this interface is +5 Vdc, whereas the 7th connector is typically N/C. I am going to test this pinout against a generic 34-pin floppy interface to 26 connector FFC/FPC using a reverse direction FFC cable and see if I am successful. I will report back once I have tested the above.

 

[Paralel]

Success. I was able to boot a 3800HD from the GoTek floppy emulator running FlashFloppy using a generic 34 pin to 26 conductor FFC/FPC adapter, a secondary adapter board, one FFC cable, and one FPC cable. As a result of the way the floppy interface is oriented in the Tandy laptops one needs to use a secondary adapter board in order to make it work with the current parts available. It is possible that with one of the pieces redesigned to eliminate the secondary adapter board. I will discuss that in my final write-up post. The necessary items that are ancillary to the GoTek floppy emulator can all be bought for less than $20. Based on this there are two ways to make this work with the current parts that are available. The current test setup I am using is inelegant. Once I get the piece I need for the final setup I will re-test to ensure it is functional and then write up both methods for how this can be done.