What Machine Do I Have? Any Info would be appreciated. Error Code #12

[DoubleDiamond]

Double Diamond

Model #IB4032C
Serial #377937
Date: Oct 1993

Game Prom #772
Reel Prom #5XDD
                 859? (4th number I can't make out)
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When powering on the machine, I have the Error Code 12 (Replace CPU Battery)
I have the battery on order.

When it arrives, do I install it rite away, or
do I need to re-install the CPU, power on the unit, power off, power on, open & close door to clear, then remove the CPU again, then install the battery ?

[Stayouttadabunker]

You have an IGT S+ Double Diamond 5 Coin Multiplier, 3 Reel, 5 Line game (5CM3R5L DD) with a "low battery" Code [12] on the display.
Turn the power switch OFF, slide out the coin hopper, then place aside.
Grasp the black plastic knob on the MPU tray and wiggle it upwards and out of the cabinet.
Take a photo of the MPU, especially where you see a battery soldered to the board.
Take note....one side of the soldered end has a (+) plus sign etched onto the circuit board.
When you solder in a new battery, you must solder the positive end of the battery to that solder pad.

It looks like you have an 86% SS reel prom award chip (SS8596) , but your award glass differs from the one I've linked here from the S+ Bible...>>>

http://www.newlifegames.net/igtbible/IGT%205%20Line/Game%20Library%20-%20S-Plus%20-%20Double%20Diamond%20(5%20Line).htm

When you replace the battery, open the door, press the little white test button 10 times to see the SS Reel chip number in the Winner Paid window on your display.

[DoubleDiamond]

Battery replaced. SS Reel chip #3824 shows in the winner paid after pressing test button 10 times.