View Full Version : Is there any practice use of the checksum and tile check of the arcade boards?
Yukio
10-10-2008, 08:00 AM
When some games are turned on , there is the start up sequence that display something on screen. Is there any mean of all those checks? There are some boards that could have a secret menu when some combination of buttons are pressed.
Is there a problem when some board fail in the tests? Some bad memory problems? There are the joystick tests for arcade machines too ...
shawnbo42
10-10-2008, 09:14 AM
When some games are turned on , there is the start up sequence that display something on screen. Is there any mean of all those checks? There are some boards that could have a secret menu when some combination of buttons are pressed.
Is there a problem when some board fail in the tests? Some bad memory problems? There are the joystick tests for arcade machines too ...
Yes, the board is checking all it's RAM's and ROM's for proper operation. If there is a problem with one, it will usually indicate which chip is bad, therefore (sometimes) making it easier to diagnose and repair.
The controls test is used for just that. Case in point is Neo-Geo, for example. If you have a game in there like Aero Fighters, it only uses button A and B. Now, If you throw in Baseball Stars Professional, it uses more buttons. So, you can use the controls test to ensure functionality of the joystick and all pertinent buttons to play the game.
jb143
10-10-2008, 10:46 AM
A checksum test is done by adding all the bytes in a ROM and compairing it to what it should be. If the checksum is wrong then that means that the ROM is bad.
As a practical example, lets say that a ROM containing graphics for level 6 is bad. If there wasn't a test when you boot the machine, then no one would know there was a problem...untill someone puts in $5 worth of quarters to get to level 6 only to find that the graphics are all messed up.
It can be a bit annoying in Mame, waiting for the imaginary tests when all you want to do is play a game, but you can just think of that as your payment for getting to play the game for free.