My Dragon cartridge boards (actually work!!!)

[robcfg]

Cool!

You know, Devil is in the details

Keep up the good work!

[Rink]

Hahahaha. Yep.

Gotta learn to read those datasheets...

[tormod]

Hi Rink,

A very nice and inspiring project!

I see on the photos that your cartridge edge connector design is not symmetrical, the right side margin (outside the metallized pad) is wider than the left side one (when looking towards the Dragon). Where did you take the exact dimensions from? A real Dragon Data cartridge?

I have noticed that also the edge connector slot on my machine is not symmetric - of the metal angle pieces confining the cartridge edge connector laterally, the left one is slanted whereas the right one is straight (see photo). I wonder if the cartridge edge asymmetry is related to this. Since the right-most pins carry 12V, maybe there is some idea that in the worst case where there is some mismatch, at least the 12V is not touching onto something else?

Cheers, Tormod

cartridge-slot.jpg (26.6 KiB) Viewed 4666 times

[Rink]

You're exactly right mate - the cartridge connector on the Dragons is bong-eyed.

First time around, I didn't realise that. I made an edge connector breakout board a while ago and it made a very poor connection in the socket. Not necessarily the wrong pins being connected - just some pins not seeming to work as anticipated due to a poor connection. At that point, I noticed the weird way the edge connector is fixed to the main board and adjusted my design to give an extra millimetre or so on one side so the board would be a better fit horizontally. I also started ordering the maximum thickness PCB from my chosen manufacturer.

It was guesstimated because the only two actual D32 cartridges I have, do not have pads/traces for every single i/o available from the edge connector - so they weren't much use to me when it came to building the breakout board.

When I came to design my rom cartridge PCB, I re-used the full edge connector from the breakout board out of laziness; didn't even eliminate the pads I didn't need. You never know when you'll need to solder on an extra wire to fix a mistake.

[tormod]

Thanks. Are you willing to share your exact dimensions?

I am looking at the full size picture from http://archive.worldofdragon.org/index. ... Cartridges and when I measure on my screen it looks like the PCB edge margins are symmetric (measured from the 2 narrow pads in the middle). Though it looks like one edge is slightly slanted (the green remainder of the solder mask narrows out towards the end). Can you or someone else having a real commercial cartridge (and preferrably calipers) please verify this?

About the thickness, I believe 1.6mm is the correct thickness. Were you able to squeeze a 2.0mm PCB into the slot?

[robcfg]

Hi!

I'm the one that added the cartridge PCB picture. I've measured it, and it's 1.6mm thick. Other non-dragon data cartridges are also 1.6mm thick.

Regarding edge symmetry, they should be symmetric, but depends a lot on the pcb maker and to be true, the pcb can take any form as long as the edge connector fits on the Dragon, and if you reuse a cartridge case, the holes for the screws are in the same place.

I've measure the pcb and updated the page, it's 102x69 mm.

Also, the top view is slightly distorted as the components move the pcb a bit off the surface of the scanner. For taking measures, take better the bottom (solder side) picture.

If you need anything else, just tell me.

Regards,
Rob

[Rink]

Nice one Rob. When I get home, I'll get the measurements from mine just in case it helps you Tormod.

Edit: from checking my orders, it is a 1.6mm
PCB thickness I'm using. Which I suspect means the other manufacturer I originally used must had a default a little thinner than that.

[jedie]

Cool project !

@Rink: Is this a DIY project? OpenHardware? With other words: Do you made all information about this public? Where?

btw. is this not a very good solution for the "bootstarp" part for a DriveWire adapters: viewtopic.php?f=6&t=4270 ?

[Rink]

@Rink: Is this a DIY project? OpenHardware? With other words: Do you made all information about this public? Where?

It's open in the sense that I won't go after anyone who copies it but I don't have schematics etc prepared yet for a complete write up.

Yep, you could certainly use it for loading DriveWire. However, If this board and my I/O boards had a child, it'd be the cartridge I'm working on now - but am having a couple of issues with the damn thing. That new board would be very handy for DriveWire