Big_P Big_p
Professional
I have repaired a few Naomi's for people, I have about 12 Naomi's in various states of working and I have a fair collection of "not tested" netdimms and dimms but have never been able to get a Naomi set up working.
The motivation to keep trying came from CVS2 and someone who sometimes frequents these parts (you know who you are) saying "I know what's wrong with it, it's an f'ing Naomi"
So to make this a real challenge I decided to take one of the numerous Naomi's I have (some of which don't work and some of which might work), combine them with a bunch of dimms and netdimms that definitely don't work and a TD-IO I built from scratch (which should work but I am not really 100% sure actually does) and put this all in the same cab as a working CPS2 multi on a jamma switch. Sounds easy right.
4 days and almost no sleep later it all works perfectly.
This thread is about documenting my learning for anyone else silly enough to try this so here we go.
1. The TD-IO works great powering a netdimm setup but the netdimm does push it to the edge of its Amp potential. You need good 17-18awg power and GND wires (not chinese fake 18awg that is mostly cover and little actual wire). The Exceleena came to the rescue here having a solid PSU and internal wiring. Even with this the TD-IO enters thermal protection after about 30min of constant running if it is not heatsinked. Finding a 4x4mm heatsink is near impossible so I cut down a copper rpi heatsink to 4x4mm and once attached to the SIC437A on the TD-IO it powers the Naomi netdimm setup for as long as I can play (at least 10hrs to date). This shows up as graphics freezing but the game nit putting out an error.
2. Buffer chips on the dimm/netdimm bottom board are commonly shot, but finding a working bottom board and top.board separately was pretty easy and the combined well.
3. Similar graphics freezing to what was noted with the TD-IO on a Naomi once you are sure your power into the system is good is either caused by bas RAM around the CPU, a bad 27mhz crystal, or a loose CPU or GPU (thanks Ken at IRepairSega). I replaced all the RAM around the CPU, put in a new crystal and reflowed the CPU and GPU and all was good in the world again. This was a nightmare to track down as it was occurring in combination with the thermal protection kicking in on the TD-IO.
4. Finally, with a TD-IO and a riddled TV jamma switch you can have a CPS2 multi and Naomi Netdimm setup in the same cab.
The motivation to keep trying came from CVS2 and someone who sometimes frequents these parts (you know who you are) saying "I know what's wrong with it, it's an f'ing Naomi"
So to make this a real challenge I decided to take one of the numerous Naomi's I have (some of which don't work and some of which might work), combine them with a bunch of dimms and netdimms that definitely don't work and a TD-IO I built from scratch (which should work but I am not really 100% sure actually does) and put this all in the same cab as a working CPS2 multi on a jamma switch. Sounds easy right.
4 days and almost no sleep later it all works perfectly.
This thread is about documenting my learning for anyone else silly enough to try this so here we go.
1. The TD-IO works great powering a netdimm setup but the netdimm does push it to the edge of its Amp potential. You need good 17-18awg power and GND wires (not chinese fake 18awg that is mostly cover and little actual wire). The Exceleena came to the rescue here having a solid PSU and internal wiring. Even with this the TD-IO enters thermal protection after about 30min of constant running if it is not heatsinked. Finding a 4x4mm heatsink is near impossible so I cut down a copper rpi heatsink to 4x4mm and once attached to the SIC437A on the TD-IO it powers the Naomi netdimm setup for as long as I can play (at least 10hrs to date). This shows up as graphics freezing but the game nit putting out an error.
2. Buffer chips on the dimm/netdimm bottom board are commonly shot, but finding a working bottom board and top.board separately was pretty easy and the combined well.
3. Similar graphics freezing to what was noted with the TD-IO on a Naomi once you are sure your power into the system is good is either caused by bas RAM around the CPU, a bad 27mhz crystal, or a loose CPU or GPU (thanks Ken at IRepairSega). I replaced all the RAM around the CPU, put in a new crystal and reflowed the CPU and GPU and all was good in the world again. This was a nightmare to track down as it was occurring in combination with the thermal protection kicking in on the TD-IO.
4. Finally, with a TD-IO and a riddled TV jamma switch you can have a CPS2 multi and Naomi Netdimm setup in the same cab.
