Cannibalizing a CV to create a mini-CV...

[Pixelboy]

A while ago, I offered a custom-made plastic casing to opcode, and after we determined that it was too small for his needs, I brought it back home with me. Later, I tried selling it in the AA forum Marketplace but that didn't work. I honestly don't think anyone on eBay would be interested in it, and I don't know what to do with it personally. It's a nice clean casing, and I'd hate to just throw it away...

 

This morning, I had an idea, but I don't know if it's feasible: Would it be possible to cleanly unsolder the main components from the PCB of an original ColecoVision console (the Z80 CPU, the graphic chip, the sound chip, the BIOS ROM, and other important components) and transfer them to a new custom PCB designed to fit inside my plastic casing? Where possible, certain auxiliary components could be replaced with smaller modern equivalents, like smaller RAM chips for example.

 

We're not talking about an FPGA solution here, because Eduardo showed me the FPGA in his MSX-on-a-chip, and it's way too big to fit inside my casing. We're also not talking about replacing the TMS9928 graphic chip with something more modern (like the V9958 or whatever). I'm not looking to realize a modernized CV at all, this would be an exact equivalent to the old CV (minus the expansion port edge connector) only reworked to fit on a PCB of a different shape.

 

This would be a one-of-a-kind item, built for fun. If possible, it would be nice to replace the RF output with something more modern. Simple A/V connectors would do, but if RF is the only solution that would work, I could live with it.

 

So can you guys tell me if it's possible or not?

Edited October 29, 2009 by Pixelboy

[ten-four]

Hi Luc...

 

Like Eduardo once said: "Impossible is such a strong word".

 

Maybe you can make contact with Benjamin Heckendorn, he can maybe use the little box.

Ben is of course as I said, good to do things in much smaller format.

 

But otherwise the little box could be good at "Pong in a chip".

[Pixelboy]

I've been looking at another alternative, namely to use this casing with a Pico-ITX motherboard, perhaps like this one. With a tiny 8GB SATA Flash drive, and a few complementary components (like a TV-out adaptor), one could have his very own super-compact living-room PC gaming machine, which could be used with MAME, or any other Windows-based emulator. I'm not sure how well it would fit inside the casing with all the extra wiring required, but it looks like it could be done.

 

Only problem is, I get a headache just trying to understand all the technical specs and hardware options. It's easy to buy the wrong component, that will either not fit with the main board, or have compatibility issues under Windows, or perhaps even fry the motherboard altogether!

[+5-11under]

Why does the case have such large holes in the front and top? What were they meant for, originally.

 

As luck would have it, I've got one of the same case, without the cut-outs of course, for one of my future projects.

 

Thanks,

5-11under

[Pixelboy]

Why does the case have such large holes in the front and top? What were they meant for, originally.

Well, this was supposed to be used for the prototype of the standalone CV that opcode (Eduardo) has been talking about. Since it was unclear where the cartridge port would be located, I decided to have a large hole cut on top for maximum freedom. Same goes for the 9-pin joystick connectors which were meant to go in front: Since I couldn't precisely predict where the two D-9 ports were going to be placed, I left a large hole in the front so the connectors could be placed anywhere. This was done solely for the prototype's sake (where ventilation was also a factor, BTW). The "real" casing would have featured proper holes to fit around the different ports.

 

As luck would have it, I've got one of the same case, without the cut-outs of course, for one of my future projects.

Nice. What kind of project will it be, if you don't mind me asking?

Edited October 30, 2009 by Pixelboy

[+5-11under]

Why does the case have such large holes in the front and top? What were they meant for, originally.

Well, this was supposed to be used for the prototype of the standalone CV that opcode (Eduardo) has been talking about. Since it was unclear where the cartridge port would be located, I decided to have a large hole cut on top for maximum freedom. Same goes for the 9-pin joystick connectors which were meant to go in front: Since I couldn't precisely predict where the two D-9 ports were going to be placed, I left a large hole in the front so the connectors could be placed anywhere. This was done solely for the prototype's sake (where ventilation was also a factor, BTW). The "real" casing would have featured proper holes to fit around the different ports.

Okay, I get it... open concept, just for the prototype.

 

As luck would have it, I've got one of the same case, without the cut-outs of course, for one of my future projects.

Nice. What kind of project will it be, if you don't mind me asking?

 

It's video game related, so I'll post some pictures on AtariAge if I ever get it done.

 

Thanks,

5-11under

[GonzoCV-1]

A while ago, I offered a custom-made plastic casing to opcode, and after we determined that it was too small for his needs, I brought it back home with me. Later, I tried selling it in the AA forum Marketplace but that didn't work. I honestly don't think anyone on eBay would be interested in it, and I don't know what to do with it personally. It's a nice clean casing, and I'd hate to just throw it away...

 

This morning, I had an idea, but I don't know if it's feasible: Would it be possible to cleanly unsolder the main components from the PCB of an original ColecoVision console (the Z80 CPU, the graphic chip, the sound chip, the BIOS ROM, and other important components) and transfer them to a new custom PCB designed to fit inside my plastic casing? Where possible, certain auxiliary components could be replaced with smaller modern equivalents, like smaller RAM chips for example.

 

We're not talking about an FPGA solution here, because Eduardo showed me the FPGA in his MSX-on-a-chip, and it's way too big to fit inside my casing. We're also not talking about replacing the TMS9928 graphic chip with something more modern (like the V9958 or whatever). I'm not looking to realize a modernized CV at all, this would be an exact equivalent to the old CV (minus the expansion port edge connector) only reworked to fit on a PCB of a different shape.

 

This would be a one-of-a-kind item, built for fun. If possible, it would be nice to replace the RF output with something more modern. Simple A/V connectors would do, but if RF is the only solution that would work, I could live with it.

 

So can you guys tell me if it's possible or not?

 

 

I'm working on a portable Coleco project. It will be based on a regular Coleco board, but I'm cutting it off almost in a straight line just past the video chip. The existing 4116 RAM array is coming off, as is the video/audio switching chip (it sources either the Coleco or expansion module to the RF daughter board). Obviously, I'll also deep six the RF board itself board and P1 controller circuitry just past the gate chip. I'll be going back in with a TMS 9118 video chip -- which can use the "two chip" memory array formed by a pair of 4416 chips -- saving a lot of space. One benefit of this memory chip swap out is that the 9118 is a direct composite out and I'll be able to skip the RV conversion board and use the native composite signal. Finally, by discarding the original 4116 memory chips and the RV daughter board, I'll eliminate the need for +12 volts. I'll still need to wire in a -5 source for the negative voltage swing on the controller circuits. I'll rewire the P1 controller and after shaving the board elsewhere I'll be able to have a much smaller board (less than 5.5 x 6.75 inches). One of the other tasks I'll be addressing for the sake of space will be to replace those giant "horned" choke components with more modern (smaller) versions. Same with the large ceramic caps.

 

I've constructed a miniature keypad (based on a mini calculator) so my portable will have full capability -I'm just too much of a Wargames fan to do otherwise. I even think I've figured out a way to wire in a rotary "gray" style encoder so as to make the steering games compatible. Video will be by the tried and true PSONE style screen.

 

I've been working on it a while, and I have a supply of 9118 video chips and the two chip memory that works with them. I'm currently working on the first "mock up" to do a proof of concept using an uncut board, and on this I'll be getting my keypad and my rotary encoder cooking with gas. If I had not been so busy the last year, I'd already be much further along.

[Pixelboy]

I've been working on it a while, and I have a supply of 9118 video chips and the two chip memory that works with them. I'm currently working on the first "mock up" to do a proof of concept using an uncut board, and on this I'll be getting my keypad and my rotary encoder cooking with gas. If I had not been so busy the last year, I'd already be much further along.

Very interesting! I'll be looking forward to seing the fruits if your labours!