NES Cartridge Battery Replacement
Today my Zelda 2 cartridge arrived in the mail, and just as I suspected, its battery was dead. So, not having any CR2032 batteries with solderable legs (and not having had any luck soldering wires directly to the contacts of CR2032s) I decided to try something different:
What you see below is a standard Radio Shack 2xAAA battery holder soldered to the battery contacts on the PCB of my Zelda 2 cart. Luckily, Nintendo decided to make NES carts twice the size of Famicom carts while leaving the PCB the same size, so there's plenty of room to store the batteries. I find myself now appreciating the design decision I formerly found rather silly. I simply desoldered and clipped the battery contacts from the PCB and then soldered the wires from the battery holder to the appropriate contacts.
A small square of double-sided tape is perfect for securing the battery holder to the front panel of the case, and small strips of electrical tape on the PCB and the panel keep the wires in order.
I am somewhat worried about how the SRAM will perform with the voltage dropoff curve inherent in alkaline batteries. But as the AAAs probably have quite a bit more power in reserve than the lithium CR2032, they (theoretically) should last a while longer. Plus, they'll be easier (and cheaper) to replace when the time comes.
Today my Zelda 2 cartridge arrived in the mail, and just as I suspected, its battery was dead. So, not having any CR2032 batteries with solderable legs (and not having had any luck soldering wires directly to the contacts of CR2032s) I decided to try something different:
What you see below is a standard Radio Shack 2xAAA battery holder soldered to the battery contacts on the PCB of my Zelda 2 cart. Luckily, Nintendo decided to make NES carts twice the size of Famicom carts while leaving the PCB the same size, so there's plenty of room to store the batteries. I find myself now appreciating the design decision I formerly found rather silly. I simply desoldered and clipped the battery contacts from the PCB and then soldered the wires from the battery holder to the appropriate contacts.
A small square of double-sided tape is perfect for securing the battery holder to the front panel of the case, and small strips of electrical tape on the PCB and the panel keep the wires in order.
I am somewhat worried about how the SRAM will perform with the voltage dropoff curve inherent in alkaline batteries. But as the AAAs probably have quite a bit more power in reserve than the lithium CR2032, they (theoretically) should last a while longer. Plus, they'll be easier (and cheaper) to replace when the time comes.