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3D Printed ST-V replacement Cart housing (WIP)

twistedsymphony

twistedsymphony

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UPDATE:
files release :) official thread here: 3D Printed Sega ST-V Multi-Cart Housing
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I started designing a 3D printable replacement cart housing for ST-V so we can use that instead of de-casing otherwise working games.

I've got the first revision of the back cover done so far (it's printing as I type this):

stv_back_rev1.jpg


I'm creating a WIP thread here because there a a number of design decisions I'd like to get some feedback on.

1. The bulge in the front of the original cart. The ST-V main board, the ST-V multi, nor any of the original carts that I've seen need this. to print easily I need the front of the cart to be completely flat. Ideally I'd like to remove the hump along the bottom of the front and slim the whole cart housing down to a uniform size. I noticed that a lot of games have an empty EPROM socket in this area and if I remove the bulge then there likely wont be room for an EPROM here. I'm curious if anyone knows of any original cart PCBs that use this lot or any other game that might have something that takes up some of this extra space.

2. the game selection jumpers are kind of annoying I know there's the remote dip board that some people use. I managed to find this right angle dip set that I'm going to be using. de-soldering the pin headers that are there now and replacing with this dip-swich setup http://www.ebay.com/itm/DIP-Switch-...hash=item256cba9e38:m:mbnaJ8-pmENusm0lvbdI3Dw
To accommodate this I'll likely add a front cover with an optional hole in the top that is big enough to accommodate the original jumpers, dip switches, or the remote dip board. Are there other considerations I should be making here?

3. there's the reset pin, and the sound wire, I'm open to suggestions on the cleanest/simplest way to integrate these pins into the cart housing.
 
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I'm nearly there...
stv_cart_rev2.jpg


taking what I learned from the CPS3 cart the first print of the back cover was only off by about .5mm on one dimension and the front cover was perfect except for the clips. I've got optional cut outs for the jumpers and SD card, however I've found that the lack of the bulge makes the front cover too shallow for the single sound output post on the multi cart (it's also too shallow for a socketed eprom in the front).

I'm still looking for suggestions for the best way/location to integrate a header for line out and reset.
 
Thanks, I might have an idea for the connector... we'll see how it pans out.
 
It would be cool if you could mount a couple of jst type connectors on the shell to make the various connections to the cart. A 12 pin for game selection/selector, a 3 pin for power for the selector and reset line and another for the update/programming pins on the cart.
 
twistedsymphony said:
Derick2k said:
for the update/programming pins on the cart.
Click to expand...
I'm assuming this is the 8 pin header on the front. Is there need to access these pins all the time?
Click to expand...
Yes, not sure, I have not kept up with the info on it, but I think DS made it so the firmware updates from the SD card automatically now. So maybe no need to access it anymore, I guess you only need to tap the reset pin there.
 
my plan is this
- a square notch in the top to allow access to the SD card
- a square notch in the top to allow access to the jumpers (large enough to support dipswitches or connectors for a remote selection device
-a square notch in the side near the speaker header. to support additional pins

I'm thinking if you take a 2 pin header and solder one pin to the line out with the other pin in some dead space that would give you a decently strong mounting point and you could then route the other side of the second pin to the solder point for the reset. that would give you a 2 pin connector off of the side.

I'm not sure why these weren't designed as pin headers on the PCB to begin with, it would have made the case design a lot easier since we could have just provided a hole to access the pin headers.

The problem with not having headers on the PCB itself is that any connector has to be panel mounted and that takes up way more space than is available inside the case and requires you buy additional hardware to make it work. The only other option would be routing a pig-tail through a hole, but that leaves you open to snagging it and potentially pulling up traces/damaging the PCB.

That's why I'm thinking of side mounting a header to the solder points on the side of the multi, they're nice big pads so they should be strong and it's the only way I can think of to add another header to the PCB... pin headers should be fairly easy to come by too. at very least they wont require you order 10 of them and then wait for shipping from Japan.
 
Here is what I've done to support externalizing the "optional" pins...

I took a remanent piece of some pin headers I had lying around and soldered them sideways off the edge of the PCB. The two pins on the bottom are soldered to the GND and Line out pads while the top pin has a wire run to the reset solder pad.


stv_option_pins_1.jpg


stv_option_pins_2.jpg


Then in the front cover I supply a notch along the edge so you can access the pins.

stv_option_pins_3.jpg
 
Here's an update where I'm at.

stv_cart_rev3_1.jpg

stv_cart_rev3_2.jpg


stv_cart_rev3_3.jpg


fitment of the PCB internally and the case with the main board is excellent. fitment of the two halves is perfect with each other and when matched up with the matching halves of an original ST-V case except for a small issue with the clips along the top which is causing a small misalignmentalong that edge. the material thickness along the cut outs in the back half is too much so I've removed some material there which should make everything snap together better.

You'll notice that I got rid of the big ugly notches in the top o the case, that's part of the reason for the misalignment because I had to guess at the clearances and was off a hair.

I'm pretty happy with where I am with this, I have the next revision with adjusted clip clearances printing now so we'll see how that goes.
 
twistedsymphony said:
Here is what I've done to support externalizing the "optional" pins...

I took a remanent piece of some pin headers I had lying around and soldered them sideways off the edge of the PCB. The two pins on the bottom are soldered to the GND and Line out pads while the top pin has a wire run to the reset solder pad.


stv_option_pins_1.jpg


stv_option_pins_2.jpg


Then in the front cover I supply a notch along the edge so you can access the pins.

stv_option_pins_3.jpg
Click to expand...
Yup, that was almost what I had in mind. :thumbup:
 
So the Geometry of the PCB and the sizing of the right angle dip-switches lead me to create this somewhat ugly solution to adding dip switches to the STV cart, the benefit is that it just plugs right in... though it kind of ruins the otherwise great looking case :P

The cart housing is otherwise done so... once someone confirms to me the dimensions of the plug end of Mits' remote board I'll make sure the hole for the dip switches have the appropriate clearances and release the files.
 

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  • stv_dip_switch_board.jpg
    stv_dip_switch_board.jpg
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Hey, awesome work there buddy. The only alternative would be to try to mount the dip switches flush with the cart edge on the top, dont if there is enough clearance for it to fit. Or on one of the sides possibly?
 
Derick2k said:
Hey, awesome work there buddy. The only alternative would be to try to mount the dip switches flush with the cart edge on the top, dont if there is enough clearance for it to fit. Or on one of the sides possibly?
Click to expand...
believe me I tried from just about every angle.... if I remove the pin header (which i discovered is an enormous pain in the ass as it appears to be soldered from both sides) then the dip switches would be sunk about 6mm from the top of the cart. not to mention it would still be too thick and poke out the front of the cart.

Using a normal vertical dip switch bank the pins are too wide to to solder to the double inline rows and would still poke out the front of the cart. mounting anywhere else would have the problem that it wouldn't be solid mounted to a PCB anywhere and there isn't enough space between the cart walls and the PCB for it to fit without poking out, the only exception to this is the area to the top right where there is no PCB, but then I have nothing solid to mount the dip switches too unless I wanted to just hot melt it to the case, even then the pin headers are too close to the top of the case that I can plug in a wire and they'd have to be removed or have the wires soldered in place.

I tried about a dozen different designs to come up with a "clean" flush mount solution and couldn't find one. so I opted for an ugly and simple solution that didn't require modifying the multiboard.
 
Man, crazy effort, it is much appreciated. I guess the only thing would be to make the cart deeper/extended somehow to fit the pins/connectors?!
 
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you could probably make a daughter board that soldered over the back side of the pin header and ran traces over to some through holes for a dip setup on the right hand side where there is some empty space... but having PCBs made up for something like that is just way more effort than I'm willing to put into this right now.
 
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