Customer originally got in touch for a recap for a Sega Saturn VA13 PAL with a Terraonion MODE already installed. After discussion, a FRAM mod and a 50/60hz refresh rate modification were also ordered. The refresh modification is an advanced feature on the MODE which requires connecting a wire to VDP2 pin 79 into the reset pin in the expansion connector of the MODE.
The first task was the recap, both of the motherboard and the PSU. One of the capacitors that came with the PSU kit was the wrong one (47uF instead of 33uF), but I had a spare one of the right type. I fed back to Retroupgrades about it
The next step was to the FRAM mod. This mod involves swapping the SRAM chip for an FRAM one, and wire pin 22 to ground and pin 28 to 5V.
To test the the mod I created a new city in SimCity 2000, turned off the console with no power cord for a couple of minutes, and turned on the console again to find our the new city still there. The save was deleted later as it was taking all the space in the FRAM chip. The battery was also replaced as it was flat and was causing the clock and settings needing to be set at every boot.
The final step was to do do the refresh modification. For this, the MODE instructions says that pin 79 of the VDP2 needs to be lifted, and a wire needs to be run between that pin and the PIN 7 of the JST connector (which is labelled as “region”). So the first task was to identify which chip is the VDP2 one, as each revision has a different IC number and potentially different chip numbers as well. Luckily, there are technical schematics online that identify VDP2 as IC14 in this revision’s motherboard. After that, identifying pin 79 was easy. The pin was lifted and a wire soldered to the pin.
The wire was soldered at the other end to a jumper wire female end, which can then be inserted in PIN 7 of the JST connector. The connection is not overly strong, so it is worth checking that the connector is firmly in place when moving the console around.
It is difficult to test if the switch of frequency is happening as described in the manual. All the games I tested from various regions seem to work well. It would be worth trying games that are known not to work well at 50hz and test that they do now work
