This project allows complete replacement of the "CAPHAT" potted module on a 48T02 RTC/NVRAM, replacing both the battery and the crystal. It uses a CR1225 cell in a holder for easy serviceability. It is only slightly taller than the original 48T02 (approximately 1.25 mm/0.05 in) which allows for clearance under mezzanine boards, such as the SBus slots on a SPARCstation 2. A full writeup on the design and instructions for installing it is available here:
https://www.glitchwrks.com/2017/08/01/gw-48t02-1
When assembled and installed on a donor 48T02 IC, they look like this:
- GW-48T02-1 PC board, use supplied Gerbers or see here for ordering instructions
- Renata HU1225-LF CR1225 cell holder
- CR1225 3V lithium cell (Renata CR1225.IB or similar)
- 32.768 KHz crystal, 2mm body, 12.5 pF load capacitance (LFXTAL002997Bulk or similar)
The above components can be purchased from Mouser. Glitch Works provides the GW-48T02-1 modules in panels or partial panels, as well as fully assembled replacement modules, and assembled/tested complete 48T02 replacements. Use the contact link on this page to order, or see here for ordering instructions.