Question about the DUO/R/RX's save data cap

[SegaSonic91]

Ahhh, so it IS socketed, thanks for the info!  It looked like the small board is slotted into a few points on the main board, but I did not want to go pulling at thing I case I broke something.  Having seemingly killed one of my RX's, that is unthinkable.

[wilykat]

I did a quick check of FRAM, it uses 2.7 to 3.3v and it would require level shifter on all address and bi-directional shifter on all data.  There are battery backed SRAM that can be used but since there's cap and switching transistor already, why go with more expensive solution when regular SRAM will work.

[thesteve]

3.3 can be used with in line resistors in most cases

[Vimtoman]

There's a guy who has done a  mod using the Tennokoe circuit.
This has Fram and binary switch.
He said he sourced a load of HUC chips.
It's called "Boostmasta+" and on the neo-geo.com forum.

I think the project may have stalled as the last update was in March.

[SegaSonic91]

I put the 1000uF cap in my original DUO-RX and tested it briefly.  It worked, after a format of the save data.  I imagine that the chips have to "power up" to hold the data?  I only played it for 50 minutes or so.  I had it hooked up to my loungeroom plasma and it was just too damn ugly to look at for an extended period! 

I still had Monbit in the CD drive, so annoyed I lost my data for that game.  I was really enjoying it.  Then I put in Gates of Thunder and played one stage followed by Travellers! for about 35 minutes.

I've already installed them in the IFU and DUO I am modding, but I was thinking of taking out the DUO one because it is over one leg of a cap and am worried about something shorting out.  I will look to buy one of the upright caps shown in this thread, rather than the short, squat round (probably 20mms in diametre) cap I have in there now.  I also thought about desoldering it and putting some tape around the area it sits above to prevent contact between the caps.