VARIANT TIMELINE ------------------------------------------------------------------------------------------------------------------------------------------------

Hopefully if you've landed on this page you've been reading through the pages of the site in order, and it will make sense why the chart below is located here. This is a visual representation of the evolutionary variants that occurred across the entire NES library as general design changes were implemented. These dates are based on Program ROM date codes found on games with these characteristics. As covered on the PCB's page, the most accurate indicator of when a game became a finished product and was packaged up and sent to stores is the PROM date code. Based on the large size of the sample of games used to create this chart, and the consistent results of the data, it is safe to say that the info here is accurate to within a few months at worst.

 

Some of the most well-known NES variants were produced during the overlap of two designs, where design elements were mixed and matched as old stock was used up, and new stock was phased in. Knowing the planned start and end dates for things based on release dates for games is somewhat accurate, but the info here is a story told by the games themselves, and paints a very interesting picture as to when all of these variants actually happened. An example of the type of info this chart tells us is the changeover from Flathead to GameBit screws and the REV-A 1 back label. I said on the Cartridge Design page that the only back label that can be found with Flathead or GameBit screws is REV-A 1. The overlaps on the chart shows this to be true (excluding REV-A 3/Zelda).

 

The chart has a lot of info crammed onto a small page, so if you click on it a larger version will open in a new pop-up window. A few games have been found to be dated into 1996, especially in PAL regions, but I cut the chart off after 1995 to save space since nothing new appeared in 1996 anyway.