Magnavox O2

[nathanallan]

I started this thread at vintage-computer and am really interested in it-- maybe recasing (as my case is really banged up) or adding some sort of I/O to it. All kinds of ideas are going through my head.

 

Also, I have come to think of these older machines as dedicted devices, rather than standalone computers. Anyway, here is my topic.

 

There is one of these in my collection, and it doesn't get much use at all. Has anyone ever tried to expand this thing? Not meaning with more "modern" attributes, but things like doubling the ram in the system, adding I/O (it doesn't really have any) or making some other kind of hardware thing for it (like a CD-ROM or networking interface).

 

It's a computer in my book, though it is mainly viewed as a Game Console.

 

LINK to pic of the machine I am talking about.

[accousticguitar]

The link doesn't work for me. The only mod I have heard of is rewiring the joystick ports so that CX-40s work. That's a mod I would like to do since I don't care for their joysticks.

[nathanallan]

Not sure why I bothered with a link. I agree about the controllers, much prefer the CX-40. They have their charm, but yeah. I was lucky enough to get a set from a later model *just the sicks) that are detachable. My system is an older one that has them attached.

 

The things in my head are recasing with a non-membrane keyboard (maybe one of those thngs like at the supermarkets, re-labelable keys),

 

add a chip to the I/O in the cart port to maybe have a serial port (or ethernet for that matter, embedded),

 

a memory card reader, maybe pcmcia or IDE interface,

 

a power LED (I guess they were too expensive back then lol),

 

y'know, make it more like a computer, but stay within the bounds of it still being an O2 at its heart (I guess like you could say an expansion like Curt's for the 7800),

[accousticguitar]

That stuff's way beyond me! I can ooh and ah when you're done, but I would be lucky to accomplish the joystick mod on mine.

[dendawg]

Why is this on the classic computer board?

[nathanallan]

It's here because I want to do something more computer-ish with the O2, and less like a game. Back in the day it was touted as a computer, and it does have that capability (even if a lot of stuff has to be done to it).

[nathanallan]

The more I read the more fascinated I become with the O2. According to Wikipedia, it has an Intel 8048 main processor, which is a 1K chip that is in the same family as the 8052, which has 4K.

 

As I understand this, that can be used for more instruction (if not a lot more) but there are more processors out there that house more memory but aren't quite compatible.

 

Oh yes, there is a lot of development life in this machine, I find. Lots of potential there.

 

http://en.wikipedia.org/wiki/Magnavox_Odyssey%C2%B2

 

http://en.wikipedia.org/wiki/List_of_Intel_microprocessors

 

http://docs.google.com/fileview?id=0ByX0R-KjYec7MWE4YjgxNTItN2E1ZC00MjE4LWI1OWMtNzMzZWMzM2I2MzEw&hl=en_GB (a google docs page)

[desiv]

I agree about the controllers, much prefer the CX-40. They have their charm, but yeah.

See, that proves I'm weird. I really liked my O2 joysticks. So much so, that when I got my Vic-20 (and my O2 had died a while before), I wired up one of the O2 joysticks to a DB9 so I could use it in my Vic-20.

 

It is in interesting concept. Perhaps even just a cart with more (cart) memory and some programming ability of some kind.

 

desiv

[+pboland]

I agree about the controllers, much prefer the CX-40. They have their charm, but yeah.

See, that proves I'm weird. I really liked my O2 joysticks. So much so, that when I got my Vic-20 (and my O2 had died a while before), I wired up one of the O2 joysticks to a DB9 so I could use it in my Vic-20.

 

It is in interesting concept. Perhaps even just a cart with more (cart) memory and some programming ability of some kind.

 

desiv

I guess I'm weird too. I also prefer the O2 joysticks. Very good tactile feel. I do prefer the silver ones over the black one. The silver ones just have the square guide, where as the back has the eight way star(?) shape to it.

 

I like that idea of this topic. I do know that a computer module was in the works for the phillips (Videopac) model back in the day. I think it ended up being a chess module and not a computer module. Not 100% sure on that one. I might need to look that up.

 

Here's a good site for that info:

 

http://www.the-nextlevel.com/odyssey2/collect/hardware/peripherals/index.php

Edited July 19, 2010 by pboland

[nathanallan]

Great link, pboland! I like the Module at the bottom of the page, though it only passingly resembles an O2 at all. Too bad nothing got released, now we just have to do it ourselves.

 

I like that keyboard, though, full clicky type, not membrane like on the O2. This is one mod I want to do, make an external keyboard for it that is more standard (but leave the membrane one in place).

[superbee]

Gorf, a friend of us (and also an AA member) is doing anything. But we´ll need to wait to know, check the link:

 

http://videopac.nl/forum/index.php?PHPSESSID=65118c61774920624cdbdbaa98e8dc24&topic=1509.0

[nathanallan]

More is occurring to me. The O2 is a basically big empty box, so that is also giving me ideas.

 

Internalize the power supply and have AC in (no more power supply brick).

 

Okay, just that one, along with the others.

 

Gorf does seem to be "on it," lol. I am watching! I registered, waiting for approval.

Edited July 19, 2010 by nathanallan

[Seob]

The pic you posted in post 10 is a odyssey 3 prototype. Released in a differed shape as the videopac 7400 in europe. There is a computermodule released for the odyssey2 that ads a cassette port to the system so you can save youre program. It's called the c7420.

The C7420 is a hardware add-on that expands the C7420 into a full-fledged home computer. The C7420 adds a Z80 microprocessor running at 3.574 MHz, 16K RAM (two 4416 16K*4DRAMs in the add-on) and 18K ROM (one 2564 8K*8 EPROM and one windowless 2564 8K*8 PROM in the add-on and one 2516 2K*8 EPROM in the cartridge). 8K ROM is being taken up by the Microsoft Z80 BASIC. Next to the two RAM chips are two additional places with the same connectors - maybe there was a 32K RAM version planned. The rest of the board is filled with various logic chips, resistors etc. which are also used for the cassette port. Of the 16K RAM a little over 14K are user-accessible.

http://www.cyberroach.com/vidpac/vidhard/new_vid_c7420.htm

[desiv]

Wow!!! Too bad they didn't release a US version (It didn't look like)...

Would be fun to play with..

 

From some of the threads I saw about it, it was incredibly slow and quirky...

 

SWEET! :-)

 

desiv

[RangerG]

An add-on to make an O2 function as an Odyssey3 or 7400 would be great (I have no idea if it could be done). There are already several games out there that have enhanced graphics on an 03, so there is an initial game line-up just waiting :-).

[+pboland]

An add-on to make an O2 function as an Odyssey3 or 7400 would be great (I have no idea if it could be done). There are already several games out there that have enhanced graphics on an 03, so there is an initial game line-up just waiting :-).

I like that idea but, something tells me it isn't doable. I would love to have a 7400 but I'm in the USA and I think the 7400 is PAL and of course the whole power supply thing. What few games a saw for it did look really good. Most of them looked to just have updated background images as part of a regular O2 games.

[+pboland]

The pic you posted in post 10 is a odyssey 3 prototype. Released in a differed shape as the videopac 7400 in europe. There is a computermodule released for the odyssey2 that ads a cassette port to the system so you can save youre program. It's called the c7420.

The C7420 is a hardware add-on that expands the C7420 into a full-fledged home computer. The C7420 adds a Z80 microprocessor running at 3.574 MHz, 16K RAM (two 4416 16K*4DRAMs in the add-on) and 18K ROM (one 2564 8K*8 EPROM and one windowless 2564 8K*8 PROM in the add-on and one 2516 2K*8 EPROM in the cartridge). 8K ROM is being taken up by the Microsoft Z80 BASIC. Next to the two RAM chips are two additional places with the same connectors - maybe there was a 32K RAM version planned. The rest of the board is filled with various logic chips, resistors etc. which are also used for the cassette port. Of the 16K RAM a little over 14K are user-accessible.

http://www.cyberroach.com/vidpac/vidhard/new_vid_c7420.htm

That seems odd that they opted for a computer module that uses a Z80. So is it basically a whole new system that plugs into the OD2? Why not use the internal processor that is already in the OD2? Does it use anything other than the keyboard and video out of the OD2? Sorry for the questions. I'm not that technically savvy.

[RangerG]

I have always liked the 7400, but it would be a pain and risky to get it to the U.S. You need to mod it and then use an adaptor. It would be a big investment with too many possibilities of something not working. It really would be fun to play the 03 games and they are all on the 02 multicart.

[nathanallan]

Doing more homework (no pictures yet, still have to make sure of my own power supply). I have found this site which I joined:

 

http://www.evatronix-ip.com/

 

They have variations of the Z80 and 68000 that might prove useful in this project and also my Networking Genesis project (remember that one?). They seem to give out samples to people that ask, so you guys who do hands on might want to join to get some cool goodies (I know I am!). But you do have to register.

 

I cant find a multimeter at the moment, so can't plug up my O2.

 

/also posted at vintage-computer

[nathanallan]

I made a couple of small videos showing this off, here is the one I did just a bit ago. No modding yet, other things are keeping me from it:

 

[+pboland]

I made a couple of small videos showing this off, here is the one I did just a bit ago. No modding yet, other things are keeping me from it:

 

If you are looking to do an AV mod, I have already done that. There is not much to it really. Three wires and some rca jacks. There is one issue I have with it however. When I use the Voice I get video noise on the screen. Only when using the voice though. Not much and it is still playable. I'm not an electronics guy and I pretty much found the connection points through trial and error about 10 years ago. Maybe some kind of filtering cap might work to fix the video noise when using the Voice? I don't know, I'm just guessing. Here are a couple of pics for you:

 

 

Edited July 27, 2010 by pboland

[nathanallan]

That's an excellent looking mod, thanks for the pics! I think I actually have those parts on hand, as well as some shielded cable to use. I think the noise may be from lack of shielding, so I will use a couple of pieces of insulated wire (couldn't hurt).

 

Any mod rocks, yours even has the labeled back panel, sweet

[saundby]

I've always thought the O2 was prime for mods. So much space in that box, and everything's easy to get to.

 

I'd really like to expand RAM and make a BASIC cart that takes advantage of the expanded RAM. It's a shame the RAM signals didn't get brought out to the cartridge port, but a mod could put more RAM in the console. That wouldn't even require changing the 8048's ROM (by putting an 8748 in instead.)

 

A higher clock speed would change so much you'd pretty much be building a whole new system in the box, so that's out, as nice as it would be. Everything is lockstepped to the video. The 8048 would be good with 3.58MHz, and memories could be swapped out for something faster, but I don't know about the video IC (the schematic I've seen doesn't say what it is, it practically looks like it just reads video ram and latches it for the encoder.) The software would have to change for the higher speed and resolution, so an 8748 becomes necessary. The encoder and RF modulator can be bypassed, with good RGB output, who'd want them? But overall this would be as much or more work as building a new video game system from scratch.

 

A nice analog RGB video output would be easy, it appears. And an external keyboard. A microcontroller running a USB port that pulls the appropriate lines on the O2's keyswitch matrix when a USB keyboard key is pressed would do the trick. It's funny, most old keyboards have an 8031 in them as a controller. The 8031 is a close cousin to the O2's 8048. The microcontroller to interface the two would be more powerful than both put together.

 

Power supply. IIRC the one it has is a linear. Ick. Plenty of room for a cool little switcher supply inside the box.

 

I'll look at this while I'm finishing my present project.

Edited September 16, 2010 by saundby

[Omega-TI]

BUMP

Too bad this thread never went anywhere. My brother had one of these units. I remember that it could be programmed and it had some B-grade games. I guess with so many different anemic machines out there, and so many others that never really 'caught on', it would be inevitable that some would end up as land fill never to be upgraded. Obscurity SUCKS!

[cobracon]

I started reading this thread without looking at the dates. Really would love to see someone attempt a ram and cpu upgrade. A cassette interface would be awsome too!!!