Can't find squat on anyone successfully performing this mod, granted I'm not finished yet but I needed some input from those more experienced. Inside the X'EYE we see this adjacent to the included composite and stereo jacks. For those who don't know the X'EYE is basically the second revision of the Wondermega for American markets. The Wondermega did include S-Video but I'm unaware of it having the same DIN/mini-DIN connection the Genesis/MD did; apparently the engineers thought they may have wanted it on here at some point and left both. At least I'm assuming that is what the second 10 pin connection is for. Found plenty of threads asking if it was possible, some useful (but obvious) conjecture at Segaxtreme but nothing concrete with documentation. The Sony CXA1145M functions as the video encoder for the X'EYE as well as the majority (all?) of the Genesis/MD consoles out there in the various renditions. The datasheet does confirm that it does RGB and S-Video but it would appear that the RGB lines (23, 22, 21) are unconnected from anything unless there is a via hiding under the IC. Here is what I've gathered so far: C237 would appear to be a capacitor (o'rly?) with the top pad (in this picture, in this orientation) running with two traces going off to R237 labeled 122 which I believe to make it a 1.2kohm resistor. The other trace runs under the CXA1145 and I've confirmed with a continuity test that it connects to pin 15 on the CXA1145 which is chroma - half of the puzzle. The datasheet calls for a 1kohm resistor so either I'm misinterpeting what the "122" means or they used a higher value for some reason. The Southern pad of C237 has a trace running to a via that connects to R763 on the picture below. Going with the nomenclature of R=resistor I'd feel safe assuming that this is where the 75ohm resistor would've gone. R764 is populated with an SMD component labeled "750" which should be 75ohms lending credence to this thought. The right half of R763 does connect to a single pad on the S-Video side of things, I haven't confirmed that it is chroma but all signs point to yes. It sure as hell isn't ground. Now what about luma? Luma is pin 16 on the CXA1145 IC which if you go back to picture #2 you'll see that pin 16 runs to a via which goes to the underside of the board: Find R736. You'll notice the top half of the component has a trace leading to a via that, you guessed it, is from the topside running directly to pin 16. It also connects directly to the left which is the top solder pad for C238 which is conveniently unpopulated. The bottom pad runs to a via that goes topside where in picture #2 you'll see emerge from in between pins 12 and 13 on the CXA1145 IC. The trace can be followed out towards the S-Video connector to another via that runs to the underside of the board to where you can see it emerge in picture #3 next to R762's left side solder pad which it connects directly to. The right side pad goes to another via which connects topside to K765's left pad in picture #1. K766 is for chroma assuming K765 is indeed for luma. Assuming the missing capacitors are 220uF 16/25v and the missing resistors are 75ohms, what the hell exactly should go in K765 and K766? K767 is clearly for ground but I'm not sure what component would fulfill the "K" designation. Anyone got any pointers here? Sorry for the ridiculous amount of information but I'm trying to document every bit of this even if it does get a bit ridiculous as well as being unaware of how to create those spiffy looking schematics I've seen l_oliveira make.
Some X'Eyes lacked the mini-DIN port needed for RGB and the 32X, most of the X'Eyes I've seen have it though. As for the S-video, couldn't you build an easily available circuit for the CXA1145 and then route the S-video lines to that? It might be easier than trying to repopulate those pads.
Someone did build a dual amps for luma/chroma but it isn't that hard to populate the pads. All but one component is surface mount and even then it isn't too difficult to wire through hole components up for the pads. Plenty of clearance inside the case and surface mount equivalents are quite pricy by comparison. I suppose I could populate it by hand with SMD parts but I see no point beyond making it look factory fresh. I just want to be sure the K prefix doesn't call for a specific part that, if simply jumped with a wire, won't fry the CXA1145. I highly doubt it but safe is better than sorry.
The Japanese Wondermega 2 uses a Fujitsu MB3514 instead of the CXA1145. The MB3514 can directly drive Svideo with a 220uf cap and 75 ohm resistor (according to the data sheet). The board was probably originally laid out to use the Fujitsu chip instead of the Sony cxa. BTW I am also wanting to add Svideo to my X'eye. Was originally thinking of using a CXA2075 and building a separate cirtcuit. After seeing how the board is actually laid out, it might be cleaner and easier to swap the CXA with the Fujitsu chip.
I've got an X'Eye without the mini-DIN, have never been able to uncover when or which build versions added/removed it. I've also heard rumors that some of the X'Eyes shipped with S-Video, which makes sense seeing the divot in the case, but I've yet to see one of those in the wild. I'd be up for playing along and attempting an S-video mod as well.
