Shawn Posted September 25, 2015 Share Posted September 25, 2015 Anyone here done the simple transistor video amp mod on a light sixer? If so how did it turn out? pics would be sexy too. Quote Link to comment Share on other sites More sharing options...
unicyclesuck1992 Posted November 21, 2015 Share Posted November 21, 2015 I Just did the simple transistor mod on my tele-games light sixer. I find it to be functional but not ideal, the picture is just a bit to dark for my liking. i have pics of the install in my galley. Quote Link to comment Share on other sites More sharing options...
Osgeld Posted November 21, 2015 Share Posted November 21, 2015 probally could fiddle with the resistors on the base of the transistor to brighten that up a tiny bit Quote Link to comment Share on other sites More sharing options...
7800fan Posted November 22, 2015 Share Posted November 22, 2015 You could use a variable resistor. Connect center wiper to the transistor base and one leg as input in place of fixed value resistor. Turn it while the game's running until the picture looks good, then shut it off and remove the variable resistor without changing the value. Using ohm meter, check the resistance between the same 2 legs you used to get the value, and look for closest standard value. Also I've seen some mod that has 75 ohms resistor on output and some with 100 ohms. Depending on TV, it may work with 100 instead of 75 or other way around. 1 Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted November 22, 2015 Share Posted November 22, 2015 Here's some pics I took of the simple transistor mod I did on a 4-switch woody a little while ago. And I drew up a quick schematic of the transistor mod for you Tbh though, I have to agree unicycle. The simple transistor mod isn't the best way to go if you want good video quality. You'd be better off doing something like the CD4050 based mod.But here's the schematic anyways. Quote Link to comment Share on other sites More sharing options...
7800fan Posted November 23, 2015 Share Posted November 23, 2015 Pretty sure 75 ohms resistor needs to be in line with video out, not to ground. Quote Link to comment Share on other sites More sharing options...
Osgeld Posted November 23, 2015 Share Posted November 23, 2015 Aye it does Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted December 8, 2015 Share Posted December 8, 2015 (edited) Pretty sure 75 ohms resistor needs to be in line with video out, not to ground. Aye it does You guys need to check again. Emitter needs a 75Ω pulldown. At least according to every I've ever read and on the 2600 I've composite modded, that's how I wired them. Edited December 8, 2015 by SwampFox56 Quote Link to comment Share on other sites More sharing options...
Osgeld Posted December 8, 2015 Share Posted December 8, 2015 all its doing is pulling down the video signal and keeping the transistor from sucking too much current though it, if your going to have one there I would think you would want one much stronger resistance, the TV is going to have a 75ohm impedance to ground as well 2 Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted December 10, 2015 Share Posted December 10, 2015 (edited) all its doing is pulling down the video signal and keeping the transistor from sucking too much current though it, if your going to have one there I would think you would want one much stronger resistance, the TV is going to have a 75ohm impedance to ground as well I actually thought that as well when I was first looking up the schematics people had drawn up for the simple transistor amplifier (I was breadboarding the circuit at the time), and anything over 100Ω's caused a drastic reduction in the black to white ratio (or Luma) and made the picture look awful. In fact, you can actually go without adding any pulldown on the emitter, but that makes the picture A LOT brighter. You would think that would be a good thing - but honestly? I've found it depends on the console. From the eight 2600's I've worked on so far, about a 1/3 of them, I removed the 75Ω pulldown. It would appear (in my opinion) that not all 2600's were created equally. Some need the extra increase in Luminance. Something I haven't tried is adding an electrolytic cap (negative to negative, and positive to positive) to terminate voltage at the end of the emitter. But, I've never found it necessary on any of the 2600's I've worked on. Which leads me to believe that the composite signal itself needs the pulldown, and not a reduction in voltage. Edited December 10, 2015 by SwampFox56 Quote Link to comment Share on other sites More sharing options...
SoundGammon Posted December 10, 2015 Share Posted December 10, 2015 I want to try 2 75ohm resistors in series from the emitter to ground and try tapping out from where the 2 resistors "join" to see what the results might be. Won't be able to try this for awhile, anyone else what to give it a go? Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted December 11, 2015 Share Posted December 11, 2015 I want to try 2 75ohm resistors in series from the emitter to ground and try tapping out from where the 2 resistors "join" to see what the results might be. Won't be able to try this for awhile, anyone else what to give it a go? Or you could just use a 150Ω resistor Quote Link to comment Share on other sites More sharing options...
7800fan Posted December 11, 2015 Share Posted December 11, 2015 Can't tap in middle of 150 ohms resistor. Quote Link to comment Share on other sites More sharing options...
Osgeld Posted December 11, 2015 Share Posted December 11, 2015 can with a screwdriver Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted December 12, 2015 Share Posted December 12, 2015 Can't tap in middle of 150 ohms resistor. Ah... for some reason that part didn't register in my mind when I was reading it :/ can with a screwdriver Sarcasm? If not, I'd legitimately like to know how that even works... lol Quote Link to comment Share on other sites More sharing options...
7800fan Posted December 12, 2015 Share Posted December 12, 2015 I guess he meant using screwdriver to split the 150 ohms resistor open and tap in the middle. Quote Link to comment Share on other sites More sharing options...
Osgeld Posted December 12, 2015 Share Posted December 12, 2015 (edited) yep and sarcasm Edited December 12, 2015 by Osgeld Quote Link to comment Share on other sites More sharing options...
SwampFox56 Posted December 12, 2015 Share Posted December 12, 2015 I want to try 2 75ohm resistors in series from the emitter to ground and try tapping out from where the 2 resistors "join" to see what the results might be. Won't be able to try this for awhile, anyone else what to give it a go? You could just wire a 75Ω resistor, and a 150Ω resistor in parallel, and just disconnect one when you want to test the other. But as I said above, anymore than 100Ω's, I've found wrecks the contrast of the picture. Quote Link to comment Share on other sites More sharing options...
Shawn Posted December 24, 2015 Author Share Posted December 24, 2015 I followed this and got nada. http://www.vintagegamingandmore.com/installation-guide-6-switch/ Quote Link to comment Share on other sites More sharing options...
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