Recently got a Model 2 Sega CD and after checking some videos on cleaning and repairing I found a comment where someone replaced the battery backed SRAM with a "Cypress Semiconductor FM18W08" FRAM chip allowing them to remove the battery while upping save space to 256kbit. Was wondering on peoples thought on such a mod and if anyone would know where to find a decently priced chip and the SRAM's location on the board.
The service manuals on the main page would give you info on the location. but why go to all this work just for more RAM space? Better to just get something like this. (http://"https://db-electronics.ca/product/sega-cd-ultra-backup-ram/")
I have the old official one which works just as well.
The extra RAM space would be a bonus in my opinion, the main reason I'd do this is so I wouldn't have to worry about ever changing the battery again.
Quote from: Absalon on May 09, 2019, 01:24:31 PM
The extra RAM space would be a bonus in my opinion, the main reason I'd do this is so I wouldn't have to worry about ever changing the battery again.
ah i see. Pretty cool idea, I just read the datasheet for more info:
QuoteA ferroelectric random
access memory or F-RAM is nonvolatile, which means that data
is retained after power is removed. It provides data retention for
over 151 years while eliminating the reliability concerns,
functional disadvantages, and system design complexities of
battery-backed SRAM (BBSRAM).
Pretty cool! I might try this mod myself and post results. Datasheet attached.
Looks like the chip isn't cheap, as the technology is new, fyi.
EDIT: found the comment (cool find!): https://www.thichvideo.com/v/bHpva3oxcXZ4VHc=.html
"
Xaranar I used the Cypress Semiconductor FM18W08 - it's a complete drop in replacement and will work with no issues. In addition, that chip is 256kbit, as opposed to the 64kbit one you get as standard in the Sega CD, so it will hold more save data. "
-SSF
The cheapest I was able to find without going to ebay is this one. https://www.arrow.com/en/products/fm18w08-sg/cypress-semiconductor (https://www.arrow.com/en/products/fm18w08-sg/cypress-semiconductor)
Thanks. I already ordered some and will be trying the mod out in a couple weeks :)
Hi been awhile, was wondering if you were able to get the mod working.
I made some progress, but I haven't been able to report back. I have about 10 different projects and five different PCB designs I'm working on currently. But Ill post back later :) I can tell you that the instructions I found elsewhere about this were definitely flawed.