thecrypticodor

Their power output is actually fine. The reason why those 3-1 things are so crappy is because they are actually switch mode supplies. You're lead to believe because of their size and shape that they are linear class 2 transformer supplies but they're just a switch mode supply and a ton of empty space. As to why they can create noise in your video output is because switch mode supplies create a ton of electromagnetic and RF noise that are supposed to be filtered out with components such as inductors and chokes. Since switch mode supplies will technically still work without them Chinese manufacturers will often leave them out to save money.

9-10V 500ma to 1a is fine. What’s more important is not buy any of those cheap small Chinese switch mode supplies. They almost never have inductors in them for EMI/RFI reduction which causes interference in analog signals. What this means is you can get interference and scrolling lines in your picture. Whatever you use should be a class 2 transformer type supply. If you can do basic soldering 9v 500ma supplies are commonly used for cordless phones you can get those used pretty cheap on ebay and just attach your own plug. Just remember the tip has to be positive. http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_sop=15&_nkw=9v%20500ma&rt=nc&LH_ItemCondition=4&_trksid=p2045573.m1684 http://www.ebay.com/itm/1-8-Mini-3-5-mm-3-5mm-Mono-TS-Male-Connector-Adapter-Solder-On-End-Plug-/191137822782?hash=item2c80b3b83e:g:asYAAOxyBvZTTbMk

I figured out why some games like Mega Man 3-6 won't start on the Gamerz tek NES. There's something screwy with the ground pad that the reset capacitor is soldered to. If you pull the negative leg out of the via and solder a wire from it to any other ground point like the cathode via for the unused diode it will fix it.

I did the easy 7800 mod awhile back. It was a little too bright at first which washed the colors out slightly but a 22ohm resistor on the video line fixed that. I'm very pleased with the picture quality. Here's some LCD shots I have more pictures posted here.http://atariage.com/forums/topic/127926-easier-7800-composite-video-mod/?p=2906575

The other two aren't regulators they're tip41 power transistors. Make sure you re-use those mica isolation strips that the originals were mounted on. I once blew either one of transistors or the regulator (don't remember which one) by having the base of one of the tip41's in direct electrical continuity with the base 7905. Some CV PSU heatsinks I've seen are separated into two pieces, a revision I assume to further isolate the 7905.

Are you using a automatic RF switch? Those automatic RF switches that Nintendo and Sega used will not work correctly on a 7800 and other older pre NES consoles. They will either not work at all or give a extremely weak signal. You need to use a shielded coaxial cable with a female f-type to RCA male adapter such as this for a best possible RF picture. http://www.ebay.com/itm/F-Type-Female-to-RCA-Male-Connector-Coupler-Coax-Cable-Adapter-Video-/291331319351?hash=item43d4b32637:g:XaYAAOSwPhdVMaBu

Almost none of those no name china switch mode power supplies have any interference reduction components. People buy these kind of supplies from china for little over a dollar and than resell them as console specific supplies. For instance I can buy any 9V 1A supply with the correct plug and polarity and and re-sell it as a Sega Master System supply. The thing is if you were using the original RF you wouldn't have a problem using that supply. RF modulators usually have interference reduction components such as chokes or inductors that would filter out that noise.

I don't think there's anything wrong with your system. I bet anything it's that cheap Chinese switch mode power supply your using that's causing that interference. Those cheap Chinese supplies almost never have any EMI/RFI filtering components to reduce on manufacturing cost. What you need to use is a class 2 power transformer.

You can actually buy new modulator if all else fails. http://www.alltronics.com/cgi-bin/item/92V017/search/SFE-10.7MJ--RF-TV-Video-modulator

Yes

Yeah the mod that guy in Turkey is the Intellivsion wiki composite mod. I have no ideal how that mod works for anybody I've tried it on multiple units on different TV's and get a horrid picture with a ton of interference. I also have tried it with the modulator in and out with no discernible difference in it's picture quality. My results

Did playing Earthbound in that clone trigger any of the Earthbound's anti piracy measures? http://starmen.net/mother2/gameinfo/antipiracy/ I've heard that it activates when played in a Retro Duo.

I've been trying some more games on the Gamerz Tek clone, and I gotta say even though it can play Castlevania 3 and Paperboy this is actually one of the worst NOAC's I've ever owned in terms of compatibility. I'm getting graphical glitches in games that normally don't have problems with clone systems like Super Mario 3, Excitebike and Bubble Bobble. Even a crappy Super Joy III doesn't have a problem playing these games. XD Retro bit's version IMO is the best out of all these $20 NOAC's. Even though it won't play Castlevania 3 and Paperboy it's the best compatibility and video output that I have tested. It's sound is garbage out of the box but that can be fixed by soldering a 1k resistor from the audio out to ground.

Just got mine in the mail earlier and tested a slew of carts on it. Caslevania 3 and Paperboy work. However I tried both the Tengen and official versions of Gauntlet as well as Rad Racer 2 and they don't work. With the official Gauntlet and RR2 carts inserted into the system it won't even power on. With the Tengen version it displays the same graphic corruption as any other clone. Quite a few of games that I have tried have problems even starting like Mega Man 3 and 4 that KeeperofLindblum mentioned if you keep hammering the power and reset buttons it will occasionally load or if you play it threw a game genie. So there's something wrong with the design of this system. You can see in the picture underneath the cartridge slot there is a 7404 hex inverter which is why Castlevania 3 now works. You can also see that there is some missing components on the daughter board in the back which is I think is the reason for the jailbars. I have a Retro Entertainment System clone from Retro-bit and those components are there and that version doesn't have jailbars.

The newer 3.0 models no longer play Castlevania 3 and have the same compatibility as any other clone. Also, the cheap switch mode power supplies that the retro duo comes with have no noise suppression and create rolling interference. The only way to get rid of it is to use a unregulated linear power supply and to do that you need to install a 5V regulator.

I just looked at the guide from the VintageGamingAndMore guide and I see it doesn't mention removing the R209 resistor. R209 also connects the audio video signals together.

You need to remove the Q202 transistor. The audio and video signals are combined before they are fed into the modulator removing that transistor separates them.

The 75ohm goes from the emitter to ground. It's purpose is to force a 75ohm impedance most people leave it out because it doesn't improve the picture any and only darkens it.

The difference between AC and DC is that AC has no set polarity, it shifts direction back and forth. So for AC to become DC a constant polarity has to be made. That's achieved either with a series of four diodes or a bridge rectifier. So which ever direction the voltage flows it corrected for and directed to the proper line to create polarity. So the only difference between a AC adapter and a DC adapter is that the AC one doesn't internally convert AC to DC. Consoles that use AC adapters have bridge rectifiers inside them that perform the conversion. Point is that any console that uses a AC adapter can use DC just fine and also the polarity of the adapter itself doesn't matter on them because their bridge rectifiers will correct for it. Also that 16.2v 955ma AC supply for the Intellivision II is nonsense. 12V 1A DC is a super common and more than enough to power it.

I pulled out my four switcher and tried Reactor on it and it does displays a bit of that interference pattern. Not nearly as bad as the picture I posted which is was on a six switch with that cap out of circut yet it's there. I replaced all the caps in it a number of years ago so that isn't the problem. That pattern isn't noticeable on any of my other systems including my 7800. So some degree of those lines could actually be normal for four switchers.

I took some pictures of the effect of the 4.7uf capacitor taken in and out of circuit. So If I were you I'd definetly try replacing that cap. My LCD has really long image retention so ignore the obvious Minecraft HUD.

Interference like that can be caused by bad power filtering. The first thing that I would try is replacing the filter caps. That big 2200uf 16v the .1uf 100v underneath it and also the 4.7uf 35v near the modulator.

http://atariage.com/forums/topic/228691-anyone-that-can-provide-the-intellivision-avcomposite-video-mod-service/?p=3216613

I hardly see drawing a PCB up in eagle that took all of five minutes of a mod that's been floating around on the internet since the early 2000's my work. If someone wants to sell these on ebay and wants compete with the two or three people who are already do it including you then can. Personally I'm not trying to profiteer off someone elses work so there's no reason why that would bother me.

I had some ColecoVision's I wanted to composite mod so I drew up the LM318 composite mod in eagle. I figured I'd share it with the comunity and added it to the shared projects section on OSH Park. https://oshpark.com/shared_projects/be3yEkND Three boards will run you $6.50.