Videopac G7000

In fact it's a gaming console with some computer capabilities. Introduced in late 1970s, it was one of the first "video game" computers publicly available. In different countries there were different names for it, so in USA it is known as Magnavox Odyssey 2, while in Europe it's Philips Videopac G7000. The name Philips Odyssey or Sierra G7000 is also known. In France, it was also released as Radiola Jet 25.
This device has small set of I/O devices: Two joysticks (connected with non-detachable cables) and alphanumeric, membrane keyboard, video output is also quite poor. Software is started from ROM cartridges inserted before powering on. Some cartridges (such as "Computer Intro") allow to emulate simple programming language.

The computer runs with Intel 8048 microcontroller as CPU, with specific software in chip's mask-ROM. Intel 8748 programmed with the same code can be used directly. Picture is generated by Intel 8245 circuit. Memory is also scarce - CPU has 64 bytes, 8245 can use 128. This allows to run simple games and only few other programs.

Manufacturer	Philips
Origin	France
Year of unit	ca. 1984
Year of introduction	1978
End of production	1984
CPU	Intel 8048
Speed	1.79MHz
RAM	64 (CPU)+128 (A/V) BYTES of RAM
ROM	1kB
Colors:	8 out of 16
Sound:	Mono, simple generator with noise.
OS:	None
Display modes:	160x200


Media:	Cartridge
		Power supply:
		Built-in power supply giving 5V DC
I/O:	Built-in keyboard Built-in 2 joysticks RF out






Possible upgrades:	None (maybe except composite video output)




Software accessibility:	TOSEC

My unit had CPU damaged (/WR line) and it was replaced by Intel 8748 EPROM-based controller. To re-program it a device for Willem programmer must be built, it is available at http://www.mpu51.com/eprom/eprom.html as MCS-48 adapter.

To use this adapter it's needed to raise programmer's voltage to ca. 6V (PCB3B - remove a voltage controlling jumper), and using it in this voltage is not much reliable too. In lower voltages it may throw only FFs or 00s while reading.

Photos of adapter and programming can be found in Videopac's gallery.

Contents:

Composite video

Starting

Links

Composite video output:

Composite video, with quite brighter colors, can be found in mainboard as well as audio signal. The exact location of pins with A (Audio), V (video) and GND (ground) is shown in the picture:

To explain - Looking at solder side: Video is the pin of potentiometer closer to shielding. The second potentiometer's pin with thick track is ground,. Audio signal is hidden partially under shielding, it's the most bottom pin in the mainboard, near a bigger ground plane.

Starting:

After powering up without cartridge there should be garbage on screen. With cartridge, a game should start. Original Philips cartridges have usually SELECT GAME screen in which game can be selected with number keys. To return to this screen from game, press RESET.

If it won't satrt, clean cartridge connector in cartridge and computer, then try again.

NEVER insert/remove cartridges when power is on!

Links

http://www.videopac.org/G7000/ - They have a PDF of manual.
http://www.videopac.org/manuals/ - Lots of manuals
http://www.atarihq.com/danb/o2.shtml - Odyssey 2 Technical page
http://web.archive.org/web/20081222114751/http://soeren.informationstheater.de/g7000/Index.html - Great technical page with assembly-language programs.
http://home.kpn.nl/rene_g7400/vp_info.html - Technical information, schematic

BEWARE! Components numbering in different schematics is different. When manufactured, different versions, revisions and countries had different numbering, so don't make mistakes by using one numbering for another board. Generally, the circuit is the same or only slightly different, but in some schematics even pins used by TTL logic chips are different.

https://archive.org/details/library_magnavox_odyssey2 - Games manuals
https://archive.org/details/Magnavox_Odyssey_2_TOSEC_2012_04_23 - Downloadable games
http://www.atarihq.com/danb/files/o2doc.pdf - Very good technical description of Odyssey 2
http://xi6.com/files/docs/ - Quite poor quality schematics of Odyssey 2 and some cartridges.