UAV Install for NTSC 6-switch Atari 2600 - Point to Point solder method

[CrossBow]

I believe the most common way that most techs will install UAVs into the 6 switch consoles, is using the 4050 piggy back method that is similar to that of the 5200. This method does work of course for most, but there are a few reason why you might not want to go with this installation method.

- The 4050 is critical in the operations of the 6 switch console as it not only has buffering for the video signals, but also is part of the main logic behind the fire button / trigger controls on these older models
- There are instances of the 4050 +5 voltages to the chip not being consistent and even being too low to power the UAV properly while working fine in the console otherwise
- Requires some tight solder work to attach the socket on top of the 4050 which again, is a critical IC in the system and 40+ years old in most of these consoles
- The 4050 is quite susceptible to ESD (Electrostatic Discharge) damage. So not using proper equipment rated to be ESD safe and setup properly can damage the 4050 when touching and soldering to it directly

Although the 4050 is a cheap IC part and still made new today in this form factor, I find it best to stay clear of the IC and I get much better and more consistent results when I point to point solder wiring from other locations back to the UAV. As such, this guide can be looked at as an alternate installation method and not the only way to do it. But this is the method I've been using for several years now to install UAVs into 6 switch NTSC Atari consoles. 

UAV (Ultimate Atari Video) Layout:-
The UAV has basically remained the same on its design and layout since around 2017 when the current revision D was released. I only use the basic UAV board in all of my installs as I find that easier to wire to and provides me more flexibility overall. Below is a diagram showing you the spots on the UAV you need to be concerned with on NTSC 2600 Installations. In all installs, the UAV will need to have power, ground, color signal, and a few other video signals provided to it for it to function properly. These signals come from the TIA chip. Take NOTE that you attach the signal wires for S, 1, 2, & 3 along the center and smaller vias on the UAV. If you have a pre-built UAV with a header block soldered here, just solder wiring to the tops of the header pins to make it easier.

Different revisions:-
The 6-switch NTSC consoles come in only two main versions. What we call the Heavy sixer and the light sixer variant. Most of the differences between the two models are on the separate attached switch boards and not on the main board containing the core logic of the game system. As a result, the method shown for UAV wiring is the same between both models of the 6-switch NTSC consoles.

Power, Ground and Color resistor:-
The UAV requires power and ground to operate. The 6-switch models also have an 800Ωish resistor located at R213 just about below center of the TIA chip. The picture below shows good points to get +5v (R207)and ground (C204 or C203) connections from. Additionally, the color resistor that is in place, must be disabled from circuit as it will cause hue/tint issues on the UAV that cannot be adjusted out using the color trimmer wheel. I usually de-solder the right leg of this resistor and use shrink tubing around it to isolate it, while keeping it in place in case the resistor should ever be put back into service for some reason. You can also just clip the leg with side flush cutters as well.

NTSC TIA signal component locations for UAV:-
The signals needed from the TIA can be gotten from points directly off empty vias on the main board or from a nearby component leg. Again, these are alternate locations that I use for UAV installs as there is plenty of room to solder everything to and it keeps the wiring from the UAV to the main board pretty short. The signal points on the UAV for S, 1, 2, 3, Co In, & Audio are shown below. You might have to carefully bend the resistors to the side a little bit to allow for more room to access these spare vias. 

Audio Connection:-
As shown in the previous picture, there is an unused via next to capacitor C210. This via is connected directly to pins 12 and 13 off the TIA and is where I tap the signal needed for the audio output. However, as this is the raw signal from the TIA it is a bit too strong and I advise adding in an additional 10µf capacitor and resistor inline to help bring the level down a bit. The level of resistance it up to you and isn't required but I wouldn't go above 10k as that is likely to be too low for use and again you might be fine with how it sounds without one at all. Also be advised that this point has both pins 12 and 13 already combined so it will only provide a mono output from both channels of the TIA audio. 

UAV output wiring:-
The output side of the UAV is along the same point that you attached the TIA color signal wire to. All of your output signal jacks will require a connection for the signal output and also ground. What I usually do in my installs is to run a shared ground wire for both audio and composite video from the ground pin near the composite output on the UAV. I then run another second shared ground for the chroma and luma outputs for s-video using the ground pin between Co In and chroma out on the UAV outputs. The diagram below shows the S-video connections on the female s-video as viewed from the front of the s-video jack.

What about that blue box thing on the UAV, what is that for? :-
The blue box near the output side on the UAV is a trimmer adjustment for changing the way color artifacting looks through composite output. However, this trimmer has no impact when used on the 2600 console as it was mainly put into place for using the UAV on the Atari 8-bit computers where more games used NTSC artifacting.

And that pretty much sums it up. The work required to install the UAV into a 6-switch 2600 in this manner might seem like more work, but I think the consistent results and less risk to the TIA and 4050 IC are worth it in these particular installs. And in the case of the NTSC 6-switch consoles, the empty spot on the main board above the TIA is a great place to attach the UAV and have everything needed right there close by. Here is an example of one I've done using the information I've posted above to give you an idea. 

Edited November 10, 2023 by CrossBow

[RickR]

GREAT write up and advice.  You are a true asset and I appreciate you sharing your knowledge.