exxos's Atari, Amiga & retro forum

HD DMA Cable

I have done a small PCB so that you can make your own HD cable. Compatible with Lotharek's PCB. Thus this also works with UltraSatan (Tested with US). I don't know if it has the same pin out as Oliviers DMA cable though. I haven't tried it. I have made two different variants of the board. I have use the one with bigger holes in the instruction below. You can also use loose pins.

Big hole PCB Gerbers.
Standard hole PCB Gerbers.

WARNING: Longer cable might/probably need pull-up resistors on the data lines on the DMA. Otherwise corruption might occur. If the cable are used on a Mega STe/TT then make sure it is not shorted on the port above the ASCI port.




Parts needed:

• One IDC 20 pin Female to IDC 20 pin Female cable in the length you want (shorter is better) or make your own.
• Two PCB (or one if your doing a Ultra Satan cable).
• Two 25 Pin D-Sub Male connectors for cables (or one if your doing an Ultra Satan cable).
• Two 20 Pin IDC Male Connectors (or one if your doing an Ultra Satan cable).

How to make it:
Remove 6 pins from one side of the DB25 connector by pulling it out with a pair of pliers from the solder side. Cut away the metal housing around it. Cut by the two holes at end and it should come apart. Cut away the end plastic were you removed the pins to make the connector a 19 pin D-Sub. I have made some red lines below so you can see what I mean. Sand it if you want it it to look nice.




Push in the DB19 you made into the PCB. It's a snug fit and it will not sit flush with the PCB. Solder the connector and then the IDC connector to the board.




Clean the board with IPA (Isopropanol), connect and try it out!

Just with loose pins


Side view

:bravo:

Nice :thumbup:

This is WAY cleaner than what I hacked together :lol:

One suggestion - if you mount the "Dsub19" port on the PCB edge (half the pins on top pads, half on bottom) the footprint becomes smaller and it'll work better with old Megafile drives (where the power cable is directly above one of the DMA/ACSI ports)

Yours *might* actually still clear it though, it looks more compact than most of the ones I've played with.

DominoTree wrote: 08 Jan 2021 20:43...One suggestion - if you mount the "Dsub19" port on the PCB edge (half the pins on top pads, half on bottom) the footprint becomes smaller and it'll work better with old Megafile drives (where the power cable is directly above one of the DMA/ACSI ports)...

You mean SMD pads and then on the edge? Sure. I can do that too and put it in this thread. I initially read this post wrong and did this instead... :roll:

Gerbers for tighter PCB

Made this a few days ago. Forgot to post it. I have ordered the PCB so it will take some time before I get it and can solder one up and test it. The IDC20 is underneath and DB19 connector at the end so should clear the power connector on the old Megafile better. I don't have a Megafile but I can at least test it with other stuff. So I will post the Gerber later. I think it says 2021 on the one I ordered though. ;) :shock:

DoG wrote: 12 Jan 2021 18:23 Made this a few days ago. Forgot to post it. I have ordered the PCB so it will take some time before I get it and can solder one up and test it. The IDC20 is underneath and DB19 connector at the end so should clear the power connector on the old Megafile better. I don't have a Megafile but I can at least test it with other stuff. So I will post the Gerber later. I think it says 2021 on the one I ordered though. ;) :shock:

Front and back edge.png

Looks about as compact as you can get :D

Totally forgot about this.

Here is the last gerber for edge connecting the DB19. The copper plates on the edge is moved a bit so it should be easier to solder. So image is not exactly as finished product. Tried and working on UltraSatan.

That's fantastic work @DoG. Congrats!