Genesis Model 2 (CXA1145) S-Video mod. Where do I get the +5 volt from?
I can pretty much do everything else, but I can't find where I would get the +5 volt from on the motherboard? I know where it exits on the composite out, but I need to find where it is on the board so I can solder a wire to the transistor.
You can get it from the CXA1145 itself on pins 12 or 19.
Attachment 6221Thanks. I see pin 19, not Pin 9.Quote:
Originally Posted by ApolloBoy
Attachment 6222Attachment 6223
However, if at all possible I'd like to find a point on the actual motherboard and NOT the that tiny IC. It is so easy to damage the IC. Trying to solder one more tiny wire might just be pushing my luck.
I go hardcore and get 5v right from the 7805 power regulator. Lately I've been getting lazy and I've been grabbing 5v from the nearest source which is usually less than an inch away from whatever I'm installing. I still love my power regulator days though. Anyway you can't get bigger solder joints than a 7805 regulator, plus there's only three pins on the thing.
Unfortunately, by the time I read this I already used the VCC from pin 12. Good news is I didn't destroy the Model 2 and the mod appears to work on my LCD.Quote:
Originally Posted by Drakon
Bad news is there are some faint vertical lines present that are much more pronounced than in they are in the picture with my S-Video mod for the Model 3 with the CXA1645 encoder.
I'm using a 68 ohm with a 220 uf on the chroma and a 33 ohm with 2N3904 on the luma.
Anything I can do to make the S-video on this model 2 look more like the S-video on the model 3?
I have the same issue with my VA7 model 1. I think it may be a result of the TV's upscaler. Eventually I may wire an s-video jack into my CRT TV and test it on that. I also plan to recap my Genesis just in case that may be the cause. Will post if it changes anything, gonna order the cap kit tonight.
That's a fairly common issue with the chroma line on the CXA1145, you could try bumping up the resistance on it. An ideal solution would be to wire up a 1K pot to act as a variable resistor, that way you can dial in how much resistance you want until the jailbars are down to a minimum.Quote:
Originally Posted by Majestic_Lizard
I have no clue how to do that (1K pot). However, I replaced the 33 ohms on the Luma with a 27 ohms that I found (to be closer to the guide). I also located a 75 ohms for the Chroma, but the lines were worse than with the 82 ohms (as you likely predicted). On the Chroma I'm all the way up to 90 ohms and the lines do appear a bit fainter, but still look like ass compared to the model 3.Quote:
Originally Posted by ApolloBoy
As was said earlier, just use pin 19 or pin 12 of the CXA1145. If you are needing 5v for the transistor, you can straddle the transistor on CXA1145 pin 16 and 19 for Luma input and voltage input. Then just bend up the last transistor leg in the direction you want the resistor and wire to be in.
Thanks for replying. Sounds like good advice. You're a little late to the party, though. The +5 volt is rigged up now, but I'll remember your advice in the future. I hate soldering on those little IC's.Quote:
Originally Posted by Guntz
Anyway, it turns out that I had to go all the way up to 120 ohms on the chroma to get the picture looking like it does on my Genesis 3 with the CXA1645.
135 ohms on the chroma now looks BETTER than the CXA1645.
Why is it only me who ends up getting Composite-quality S-Video when adding a resistor to Chroma? Whenever I do so, I get a very blurry image with a heavy amount of fringing. Majestic, you don't get this, do you?
What apolloboy says is true, I discovered the 32x gets rid of the jailbars magically when you s-video mod your 32x. I used 220 ohms on chroma with my genesis, only for sms stuff that can't be played through the 32x.Quote:
Originally Posted by Majestic_Lizard
Either your tv is messed up or you're accidentally wiring a filter into luma somehow. Chroma won't effect sharpness of the image at all.Quote:
Originally Posted by Ace
Not on my 32 inch Magnavox LCD (which was FREE).Quote:
Originally Posted by Ace
However, I noticed that when I switched the resistor to 130 ohms, ALTHOUGH the bars were greatly reduced (even more than on my Genesis 3), the Master System games went to black and white (with flashing color). LOL. Not worth it to mess with it anymore. Just getting the wires organized to fit in the case was a nightmare.
BTW: The vertical bars are only noticeable if you are standing about two feet away from the TV, otherwise they aren't noticeable.
Well that makes no sense. My va6 is using this circuit with the cxa1145 for master system games:Quote:
Originally Posted by Majestic_Lizard
http://imgboot.com/images/Drakon/cxa...edcircuit2.jpg
And it looks fine no blinking or anything crazy.
Old circuit:
http://imgboot.com/images/Drakon/1145svidyuck.jpg
More resistance on chroma:
http://imgboot.com/images/Drakon/1145revised.jpg
Update: Confirmed working on Model 1 (non TMSS), and it looks even better. Really hard to see the vertical lines on this model 1.
First of all, thanks Drakon. I changed the 130 for a 220 ohm on the Chroma and it looks a lot better. As far as the Master System games, I don't know what to tell you. However, you are referring to a model 1, I believe. I'm on a model 2 and that might be significant. Also, your mod is quite different. You are using a different transistor and different values for the resistor on the luma.
Also, I have nowhere NEAR the level of vertical lines that you are showing in your images. You can barely see them at all.
http://www.youtube.com/watch?v=8TpMFfMbFqk
http://youtu.be/kJ-4kxhIxZU
NOTE THAT THE COLORS DO NOT LOOK LIKE THAT. When shooting video of an image on an LCD with my cam I always get wavy lines and funny color that are not visible in person.
Here is the way I'm doing it:
Attachment 6237
As far as the master system goes, I can only guess that it is a weaker video signal from the the Z-80, therefor when you increase the resistance to fix the lines coming from the primary VDP, you then have issues with the Z-80 graphics. But I'm just talking out of my butt. I really don't know. Just for the hell of it, I'm going to make a switch to flip between 68 and 220 ohms in a bit.
Okay, I just confirmed it. Using 220 ohm on the Chroma and 27 ohm on the luma, I get almost NO jail-bars on Genesis games. And to see the jail-bars you have to stand really close to the LCD. However, Master System games have color problems. With 68 ohm, you get some jail-bars, but the Master System games have no problems.
I just made a switch. I can now switch between 220 ohm and 68 ohm on the Chroma, and sure enough I can turn the color on the Master System games on and off. On the Genesis games, it turns the vertical jailbars on and off. Also, on 68 ohm the jailbars on the SMS games are nowhere near as pronounced as they are on the Genesis games with 68 ohm. I can only guess there is a difference between the origin of the video signal between the two. Whether or not it "makes sense", it's true.
As far as Drakon's images, Sonic 2 on my S-Video mod has vertical lines so faint you wouldn't even know they were there unless you knew to look for them. Maybe it's my LCD? Dunno.