Sega model 3 - Step 1 and 1.5

[davidcoolman]

Dear all,
I need info on the CPU and GPU boards of these two revisions please. The info available on segaretro is scarce regarding model numbers.
If you have pictures of which is which it would help aswell.
Thanks by advance
best. D.

 

[ekorz]

https://github.com/mamedev/mame/blob/master/src/mame/drivers/model3.cpp

 

[stj]

that mame info is a bit contradictory!

 

[davidcoolman]

Thanks, so accoring to the mame driver:

837-11858 MODEL3 CPU BOARD
837-11859 MODEL3 VIDEO BOARD
837-12874 MODEL3 STEP 1.5 CPU BOARD
837-12875 MODEL3 STEP 1.5 VIDEO BOARD

it gives me a good starting point but if some1 can confirm by eye, it would be awsome

@stj how is it contradictory?

 

[stj]

it says there is no 1.5 boards,
and then goes on to say that the "1.5" boards have different custom chip versions.

 

[davidcoolman]

it says there is no 1.5 boards,
and then goes on to say that the "1.5" boards have different custom chip versions.

my understand is that step 1 and 1.5 can be considered as original Model 3 (though specs are different... )