EEVblog #491 - Nintendo 64 Game Console Teardown

[FrankBuss]

Nice board layout. They managed to do it with just two layers. But I guess not that difficult, if you can design your own chips.

[Rerouter]

as far as console CPU decapping goes, is there a reason why its been avoided on much more complex things like an Xbox? is it the sheer area of the die or is it more than there are many many layers,

[marshallh]

as far as console CPU decapping goes, is there a reason why its been avoided on much more complex things like an Xbox? is it the sheer area of the die or is it more than there are many many layers,

Well the Xbox cpu is just a Pentium III, and the graphics just a nVIDIA derivative. Even so, you are right that more modern high-current packages typically have more complex power delivery structures. For example, graphics ASICs in the last 10 years or so have power and ground metal meshes laid over the die. It is really annoying to try to get around these and while it's no problme for those with the right tools, it makes it harder for the hobbyist decapper.

[David]

I got half way through reverse engineering the N64 PCB in order to make my own portable version. This information may be useful to some people (not my own):

On the early N64's (NUS-CPU-01 to NUS-CPU-04) the DAC and Video Encoder chip are separate. the DAC is labelled 'VDC-NUS' (Or 'VDC-NUS A') and takes the digital video data directly from the RCP and outputs RGB. This RGB is then sent to the separate 'ENC-NUS' video encoder chip wheres its encoded into Composite and S-Video. It is possible to perform an RGB mod on these consoles because you can tap the RGB signals from inbetween these two chips.

The AVDC-NUS (NUS-CPU-05) combines the DAC and the Video Encoder together into one chip (It actually also combines the Audio DAC aswell) Which means that it converts to RGB internally and then encodes directly into Composite and S-Video - so there is no way for us to tap into the RGB signals anymore   

The Video/Audio chip progression seems to go like this:-

NUS-CPU-01 to NUS-CPU-04 (Early-ish NTSC N64's)
VDC-NUS - Video DAC
ENC NUS - Video Encoder
BU9480F - Audio DAC
-------------------------------------------------------------------------
NUS-CPU(P)-01 (Early PAL N64's)
DENC-NUS - Combined Video DAC and Video Encoder
(The DENC-NUS chip was only ever used in PAL consoles)
BU9480F - Audio DAC
-------------------------------------------------------------------------
NUS-CPU-05 (Mid NTSC N64's)
AVDC-NUS - Combines Video DAC, Video Encoder and Audio DAC into one chip
(The AVDC-NUS was only ever used in NTSC consoles)
-------------------------------------------------------------------------
NUS-CPU-05-1 onwards (Late NTSC N64's) and NUS-CPU(P)-02 (Late PAL N64's)
MAV-NUS - Combines Video DAC, Video Encoder and Audio DAC into one chip
-------------------------------------------------------------------------

The AVDC-NUS and MAV-NUS chips seem to share exactly the same pinout. It is my guess that they are both almost identical and only differ in that AVDC-NUS chip can only use NTSC color encoding (Just a guess) whereas the MAV-NUS can do both PAL and NTSC color encoding by making one pin high or low.

[lilshawn]

The "jumper pak" is just terminating resistors and loopbacks for the flyby serial interface and clocks.

yes, absolutely correct.

Anybody else remember RDRAM memory? you had these continuity "dummy" sticks to terminate the bus (called CRIMMS) to continue the signal to the termination on the main board... same thing here, you need to have the "jumper pack" installed (or the memory expansion) to have the RDRAM operating. This is why you are seeing no action on the ram.

[andersm]

The team that designed the N64 chipset later went on to found a company called ArtX, where they designed the GameCube graphics chip for Nintendo. ArtX were bought by ATI, where they worked on the Wii's graphics chip and the Radeon 9700.