In fact, I'd love some advice for modding a Samsung HiTron TV-488. I'm not having any luck finding the service manual, but it uses this Philips IC (TDA8841) -
https://my.mixtape.moe/hiflqk.pdf.
(This post was a mess,so I've tried to clean it up from here)
What I'm doing -
Feeding PSOne Luma to the secondary AV line - shows up as B&W
Feeding 5V to pin 26 of the jungle chip - blanks the display
Feeding RGB to pins 23 thru 26 after that - does nothing, no image appears at all.
However, feeding amped RGB onto the output pins of the jungle chip instead (pins 20 thru 22, nominally 2Vp-p) shows a stable picture, but it's not a great picture. It starts very bright with retrace lines, and then fades away to a very low brightness level over a few minutes. Disconnecting and reconnecting things sometimes brings the image back up to retrace brightness.
I'd really prefer to use the chip's RGB inputs, if anyone can help...
EDIT: ok, so looking at the PCB, the Micom feeds the neckboard directly, it doesn't feed the jungle chip. Its outputs meet up with the jungle IC outputs and thence to the neckboard. There are components missing on this revision that would allow it to feed the RGB inputs of the jungle IC, as well as/instead of the outputs - it looks like all you'd have to do is swap over one diode for each colour to fork to the inputs instead. If i did swap those... what would happen? I wonder if there's a way to turn on the RGB inputs? or am I using the wrong blanking pin?
EDIT: Ok, the Service manual is here -
https://my.mixtape.moe/zwwyvm.pdf Taken me months to find it, and finally, once i post here, i clued into something. My has the TDA8841 one chip, NOT the 8842 as shown. And the Micom is the non-TTx version, on the very last page. There might be a different manual for the Australian version, with the 8841 shown. Maybe it doesn't have the RGB inputs enabled?
it should work on the secondary AV channel? I can't get to the primary one (rear of the set) without the remote...unless pulsing something into pin 41 of the Micom will do something... anyone know how to do that? +5V logic level?
EDIT: No dice. I don't think this jungle IC takes RGB in, though the schematics from philips say it does. Or if it does, it's being blocked over the I2C bus. That's why the Micom feeds it's own RGB to the neckboard. I should test the levels of that, i suppose.