I recently got a Atari 2600 Jr. black, version PAL, equipped with a TIA C011903, making it eligible for RGB modification. Some of you have even reported to me that you have successfully used the converter on an Atari 2600 Jr.
As a reminder, PAL Atari 2600s have a palette of 104 colours, NTSC versions of a palette of 128 colours and the SECAM versions of… 8 colours Only!
The RGB converter works on my Atari 2600 Jr, so we can use the RGB mod on PAL versions, but unfortunately since only the LUMA signals are taken into account, it's a bit like converting it to SECAM 8 colours!
As you can see from the screenshot below, the image displayed at 1920 x 1080 (with an upscaler) is very beautiful, but the colours... oh yes, they're a bit jarring, aren't they?
Fun fact, if I switch the console to black and white, the colours change, but they're still just as flashy:
In short, if you're planning to modify your Atari 2600 Jr, bear in mind that this mod won't restore the correct colours. To my knowledge, there's an RGB mod for PAL versions, but it seems more complicated to install. (and more expensive) https://etim.net.au/2600rgb/
Failing that, to preserve the original colours, you may need to go through a Composite mod, clearly simpler to manufacture and install (in theory, a transistor and two resistors are enough) but at the cost of a blurrier image.
Perhaps I will propose a composite mod my own way in the near future for the Atari 2600 Jr PAL.