Elektra
Bally, 1981Trying to revive an Elektra with bad acid corrosion for someone, not too experienced / confident on old Bally. I want to install a remote battery pack. I have a diode with band towards + terminal on board. But how do I actually mount the battery pack? The original blob of acid appeared to have 3 terminals, not 2.
Do I put - of battery pack to non banded end of diode, + of battery pack to - of board, and ignore the middle terminal on board?
If you look at the back of the board, the middle terminal is connected to the + terminal. It's there so the board could support two different lengths of nicad batteries. i.e. those two terminals are the same thing.
Black lead (negative) of the battery pack goes to the right terminal which is the ground connection of the MPU board.
The non-banded side of the diode goes to the positive (red) lead from the battery pack.
For simplicity, the banded side of the diode goes to the + terminal.
However this puts resistor R12 in series with battery power to the U8 RAM chip which results in a slightly lower voltage at U8.
Probably better off hooking up the banded side of the diode to the top leg of resistor R12 to bypass it so the U8 RAM gets full power from the battery pack. FYI, resistor R12 is directly above the + terminal.
Hope this helps.
Skip the battery pack and just put in NVRAM. The RAM is socketed, so it's as easy as just pulling out the ram chip and replacing it with the NVRAM module.
I'm definitely all for NVRam, and have it in all my games. But this is someone else's game, and the main thing is to get it playable again without dragging things out with multiple iterations of ordering parts etc.
*FWIW if anyone's looking at the pic funny, the diode doesn't live there permanently sticking up, was just trying to get something quick and testable and couldn't put alligator clips on the battery terminals. It's now removed from the board and put at the battery pack.
Thanks for the help!
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