Buoyed on by my successful project to add a composite video output to a 1976 Pong game, I decided to move to my next target, the Atari 2600. Now, this little beauty needs no introduction, a classic console if ever there was one. Like many of its time, RF output was your only option and the (very long) cable came pre-connected.
The Atari 2600 doesn’t generate a particularly strong RF signal and it’s nigh-on impossible to get it (mine anyway) reliably tuned to a modern LCD-based TV with an analogue modulator. Some future-proofing is required.
After what seemed like an age, I had gathered that this was not an uncommon project. In fact, there were a variety of solutions, some ridiculously complicated, others just a bog-standard transistor amplification circuit. My chosen solution definitely falls into the latter category.
Full credit to Brighty83, a contributor to Retro.MMGN.com, who designed this mod. I’ve, ahem, borrowed a couple of his/her images for this because frankly they were better than mine. For the original source, visit http://retro.mmgn.com/Atari-2600/Forums/Atari-2600-AV-Mod and read up on the second modification posted; that’s what I’ve done here.
This particular composite hack is for the Atari 2600AP, a.k.a the PAL ‘Vader’ console. It does not apply to the original Woodys or the Jr. However, the principle remains the same on all. Find the generated composite signal and amplify it. However, for this to work you have to disable the existing RF output. It makes for a tidy installation but is destructive in nature.
Everything centres around the TIA chip, famously codenamed ‘Stella’ which became the unofficial name for the entire 2600 project. This generates the signals we need and also the mono audio. A key difference of the TIA’s layout is that it differs between the NTSC and PAL versions, so many a UK project was halted by this unrealised fact. So, to repeat myself, the modification is only for the black-fronted ‘Vader’ console with PAL output. If you can’t find the bits of circuit I refer to, step away from the soldering iron.
- 1 x 2N3904 Transistor
- 1 x 3.3K Resistor
- 1 x 2.2K Resistor
- Small piece of stripboard
- Some wire
- Phono plugs
Ok, stick the soldering iron on to 11, repeat to yourself that anything you now do to your beloved Atari is your fault and your fault alone, avoid coffee and here we go. First make up your little stripboard circuit to this specification:
(You could make it a lot smaller that than if you wanted to)
Now disassemble the 2600 and remove the shielding from the top and bottom.
Next you need to remove some components. Take a deep breath, grab some snips and remove…
- Q201 (three-pin)
You should also now remove the ASTEC modulator box. This is a tricky thing to do, take your time.
The next bit is quite easy. Locate the line of solder points marked 1-5 by the now-absent RF modulator. You’ll use these to hook the 2600 up to your stripboard as follows:
Pin 4 = Video
Pin 3 = +5v
Pin 1 = Ground
Now for the audio. On the reverse side of the board, locate the pin highlighted ‘A’ and solder to a direct audio line-out from the system. No extra gubbins required.
Give it a test and when you’re happy, get the drill out…
Done! Yes, I know the phono plugs are a bit blingy but it’s all they had in.
Anyone for a game of E.T.? Thought not.