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#1
27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 7:50
PVB Elite
Joined 2010/1/5
Sweden
560 Posts
Long Time User (9 Years) Donator30+ Game Ratings
I've spent most of the night doing this (no, not the wife)...


Key-part is the cut down 2x40 connector 2.00 mm pitch (distance between center of pins).
It was manufactured by a company called Prostar and model number is FH-2MM-SD-2X40-G

Elfa.se has it and it should be available at other electronics firms as well.
Datasheet:
https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/04379177.pdf

If there is a 2x30 as well it ought to be called FH-2MM-SD-2X30-G - something to google for perhaps. The little knob I left on one side of the connector isn't really necessary as far as I could see.

Eprom is a plain 8/16 bit 27C160. As DIP it's only available as uv-version or One Time Programmable. I bought four 50ns chips (they had 120ns or 50nd - faster is always better, right?) from eBay for $19.90 which is much cheaper than anywhere else - they are used but it doesn't really matter - they were erased and ready to use. It was basically just pin to pin from eprom to connector, they layout was exactly the same except for one extra ground pin in the middle of the eprom on one side. It's very quick and easy instead of using double eproms and having to split files and so on.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230411862437
There's still plenty of eproms - you need an extra adapter though if you use the affordable Willem programmer.


It took a while to build it...

As I built this with no intention of using a case - size is the same as the outer dimensions of an original cart - (I might however mold it in with epoxy or just spray it with protective lacquer) I noticed there was poor connection when wiggling it a upwards and downwards (as there's no case it can move about 2 mm both ways. So I sanded the front of the connector down a bit to increase chances for a good connection with 33% (there are three surfaces that are supposed to touch the male connector pins) - as the pins then also reaches the bend in the back of the connector. After that there was no problem, I could only make it crash if I pushed it up as far as it could go - some epoxy or other kind of spacer will solve that - not that it's a problem as you rarely play up-side-down...

I could also have loosened each connector part and squeezed it a little tighter, but I didn't feel like it. If there's a shell it wouldn't be able to move anyway so probably not an issue.


So - first try was Red Alarm (U) - first VB game I ever tried - really really nice - a little jerky game though - and it's totally unplayable in Reality Boy - why is that? I got a little Vectrex feeling out of it. It would have looked better on a Vectrex ofcourse...

YouTube movie:
http://www.youtube.com/watch?v=B6-LxTttZgQ


And oh... if anyone wants me to make one for them, that can be arranged. In that case I'll make a proper PCB for it though, if there are many people interested it will be a little cheaper.

I spent about 360 SEK for all parts, not included solder and wires - I already had that. A ZIF-socket would be more convenient but they're usually really expensive and I'm not sure there room for one unless you make the board longer.


HowTo:

Attach file:



jpg  DIY eprom cartridge.jpg (660.61 KB)
1239_4b69198f5a6b5.jpg 550X2949 px
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#2
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 9:25
PVB Elite
Joined 2003/7/26
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Hey, that's a sweet looking build and an excellent write-up with great photos!

I'm kinda surprised that the connector works right, considering the real connector has two different spacings (the rows are only like 1.4mm apart). I hope you don't damage your VB's connector doing that...

I know nensondubois will be happy, though
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#3
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 9:56
PVB Elite
Joined 2008/11/10
Great Britain
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ContributorLong Time User (10 Years)
Nice work there fella.
Top job in tracking down a connector, the possibility of making up carts totally is now there.
I have been thinking of cnc machining some cart cases, well I model it up and a work mate does the cnc bit, and to use that connector type would be great. Def something i will be filing away for future projects.
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#4
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 11:56
PVB Elite
Joined 2010/1/5
Sweden
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Long Time User (9 Years) Donator30+ Game Ratings
The openings of the holes on this connector are larger, so the 1,4mm vertical spacing as you say seems to be no problem. I haven't noticed any bending, neither any problems using regular carts.

Perhaps this one isn't the best, cheapest or easiest way to go since you have to modify it slightly to make it work well.

It works for me, but a FlashBoy is still the best way to go if you want to be able to play any available game. If you can afford it that is.



How about CNC:ing molds instead, to mold new cart shell halves? ;-)
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#5
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 13:27
PVB Elite
Joined 2008/11/10
Great Britain
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ContributorLong Time User (10 Years)
Quote:

How about CNC:ing molds instead, to mold new cart shell halves? ;-)


If i had access to mold facilities I would def give it a go, but i'm in metalwork engineering so all i can get done as rabbits are machined parts.
Also making molds is not something i have ever tried.
Once i got the cnc program sorted it should be fine to run off batches of cases, and indeed once i have the 3D model etc done anyone else is welcome to use it to make thier own.
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#6
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 14:55
PVB Elite
Joined 2008/12/28
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One word:
Sweet!
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#7
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/3 22:17
PVB Elite
Joined 2003/7/26
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Quote:

Quote:

e5frog wrote:
How about CNC:ing molds instead, to mold new cart shell halves? ;-)


Hedgetrimmer wrote:

If i had access to mold facilities I would def give it a go, but i'm in metalwork engineering so all i can get done as rabbits are machined parts.
Also making molds is not something i have ever tried.
Once i got the cnc program sorted it should be fine to run off batches of cases, and indeed once i have the 3D model etc done anyone else is welcome to use it to make thier own.


It would actually be quite difficult to make a mold using CNC, given that a round cutter can't cut square inside corners (although you might be able to get by without any on a VB cart). But, you could machine positive masters from which to cast molds, which could in turn be used to cast cart shell halves.

It's been on my back-burner for a while. I have the stuff to make silicone molds, and plenty of wax from which to mill masters, but the only thing I have to cast in the resulting silicone molds is something called Excalibur, which is similar to plaster. It would make a nicely detailed cart (showing all the flaws produced by my cheap mill ), but it would be rather more brittle than a nice thermoformed resin, e.g. ABS.

I think someone here suggested potting the cart PCB in a VB-cart-shaped blob of something. That might work with the silicone I have, if I can prevent it from sticking to a silicone mold. (I suppose I could cast the mold from Excalibur...) The only caveat would be that the silicone is a sickly pink color, and AFAIK, no paint will stick to it.

Of course, all of this requires models of the cart shell halves, so get to work!
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#8
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/4 11:06
PVB Elite
Joined 2008/11/10
Great Britain
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ContributorLong Time User (10 Years)
Quote:

RunnerPack wrote:

Of course, all of this requires models of the cart shell halves, so get to work!


Sir, you command, I'll supply, well in my own time when i can be arsed.

The cart is my next 3D model project, i'm still working on the controller, which is coming on but still tricky getting smooth results on the back, I think i just gotta approach it a different way, not figured what that way is yet......
I also need to make up a screwdriver to take a cart apart, mmmm i wonder which cart i will do that on, maybe my first issue dragon hopper cart or baseball, tough one that.
Ha ha got you i would never open up my baseball......

Sorry off on a tangent there, once i have a cart shell modelled i will happily send it to any folks who want, i can export to various formats so sharing should be cool.

I'm liking this little project, would be nice to have a complete cart in a shell made without any donar parts, just out of pure interest that it can be done.
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#9
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/4 14:36
PVB Elite
Joined 2003/7/26
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That's cool, Hedge. I can definitely wait for the cart shell models if it means also getting that sweet controller model

I personally want to be able to make cart shells that are longer, or with thicker sections to hold custom goodies, like on-board connectors (think Cardbus/PCMCIA cards).

One suggestion: it would be cool if you started an account on http://www.github.com/ (or used the one you have?) to share your models. That way, if you wanted to update/correct/add to them later, it would be easy for everyone to get the changes. Plus, we could download a ZIP of all your models with one click.
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#10
Re: 27C160 (16 bit eprom) cart build without donor cartridge
Posted on: 2010/2/6 0:59
PVB Elite
Joined 2010/1/5
Sweden
560 Posts
Long Time User (9 Years) Donator30+ Game Ratings
Screwdriver for the cart?

Buy a bit on eBay or melt the top of a bic pen with a lighter and press it over the screw. ;-)

... and the spend your time on a near perfect 3D model of the cart...
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