RGB Mod for 90’s Philips sets

Warning: This mod has an issue with SOME devices (notably, an Amiga 500) because of the improper termination. Scroll down to the comment section for an explanation and potential workarounds. The issue is only a little noise, it’s not harmful or dangerous in any way.

This shows an RGB mod for a Philips 14GX8518. The chassis it uses is an Anubis S DD. The steps to modify it are the same for all TDA8362 based sets. I’ve also successfully modified the 25″ version of this TV (Philips Powervision family).

Theory of RGB modding via MUX

This mod was performed using the MUX method. This injects the RGB signal in the Jungle IC. Sets from the 90s to early 00s usually have RGB inputs for OSD we can abuse. They were actually used more in europe for SCART RGB and for Teletext. In markets outside Europe it’s mostly used for RGB since SCART or Teletext weren’t very popular outside europe.

The theory is explained here.

Sets after mid 2000s usually don’t have a RGB input since all of it is handled by a single uC + Jungle chip, all-in-one, and since it doesn’t need to handle RGB inputs or Teletext, it doesn’t have these inputs. Some do have a YPbPr which is almost as good, and it’s possible to convert from RGB to YPbPr with an analog converter. But this is beyond the scope of this mod.

Checking the schematics

The relevant part of the schematics are the OSD output of the uC

As we can see, it uses 8k2 resistors in line with the OSD, and it doesn’t use diodes. In the CRT Database table linked earlier, we can see that for this value we can use a 1032 ohm inline resistor to inject our signal. I just used 1K. Note also the 6714 diode. We can safely inject our 5V blanking signal at the cathode.

Then we need to look at the input section of the jungle IC

As we can see, the 2280, 2284, and 2285 caps are inline with the OSD signal from the uC and they go to pins 22-24. We should inject our signal BEFORE the capacitors. Finally, pin 21 is for blanking. Just need to inject 5V via a resistor here.

Notice I’m using a 150R terminator resistor. Usually you need 75 ohms but I found it to be too much. The image is too dark if you use 75 ohms. I was using 2×150 in parallel, so I just cut one, and it was perfect after that.

Hardware section

First of all we’re going to have to add the connectors for this. I like to use separate RCA connectors but you can use a SCART if you prefer. Some people also use a DB-15 VGA connector so they can use these with hacked drivers that output 15khz sync directly from a PC.

I decided to use a piece of PCB material to mount my connectors.

Final tests

Let’s hook everything up

And turn the signal ON

It seems to work 🙂

Relevant manuals for this chassis and TV