But how do you tell how old yours is? Inside all the Game Gear they have a date and month moulded into the plastic case on the front and on the back, you would think this gives the exact date of the console but it doesn't! This date was the manufacture of the case not the date of the actual console itself, we have to turn to the Serial number on the back. Not so easy as they didn't have a concise catalogue. But from my personal experience of the console I have come up with this information. The cases were manufactured from 1990 to 1996 and many were used in newer mother boards so all through the lists you can have a new mother board in a old case. They were just using them up!
Early Mk 1 consoles (Flat front screen) had a letter at the start B or Z the next character isn't a letter it's a number 0 then follows the actual set of numbers starting from 1. This denotes the console as being made in 1990, so using this scale you can follow each unit to 1996.
B0 1990 onwards Z0 1990 onwards
B1 1991 Z1 1991
B2 1992 Z2 1992
B letters had transitions from the Mk 1 So you can have a B1 with a flat screen.
It all looks very simple! But wait. The Game Gear was also manufactured in the USA (Taiwan) , the only other place it was made outside of Japan. They were exported around the world, and not excursive to the USA. So you have a set of whole new numbers.
P letters had transitions from the Mk 1 So you can have a P1 with a flat screen.
Hang on! My console has a K letter, what's this? Again this is from the American market, but follows the same rules.
K models didn't go beyond 1993, and seem exclusively a Mk 2 model.
But again more numbers just to confuse you! There are also a set of consoles with no letter denomination at all. These all started with a number, this can help identify the date also Serial numbers starting with 0 are from 1990.
Console numbers after 93 then changed to another number so 94 is 1 then 4.
Again transitions you can have a Mk 1 console with 2 number.
And the set of numbers from the Australian market. AB
And finally the Mejesco numbers.
AG91 the number 1 denotes the date 2001
I hope this helps identify the age of your console and if you think any of the information needs updating please let me know. as I say this has only come from personal experience of selling and repairing 100's of consoles.