Apex AT2408S
Apex AT2408S CRT RGB mod
This tutorial covers the RGB mod for the below models. This mod was performed by a fellow redditor (freqhog).
- Apex AT2408S
CRT safety
Caution
You can die doing this! So read carefully! CRT TV is not a toy. Do not open a CRT TV. If you don't have any prior knowledge about handling high voltage devices, this guide is not for you. CRT TV contains high enough voltage (20,000+ V) and current to be deadly, even when it is turned off.
Plan of attack
Service manuals
AT2408S Specs
- Chroma (N301): OM8839
- OSD (N001): CH04T1009
AT2702S Specs
- Chroma (N301): OM8839PS (pin 23, 24, 25, 26 for R, G, B, Blanking)
- OSD (N001): CH04T1002 (remove 330ohm to ground for RGB mux mod)
Schematics
Get hold of the schematics for your TV. Understand where the RGB and Fast Blanking signals go from OSD to the Jungle (Chroma) chip.
PCB
Points where the R, G, B and Blank wires should be connected are marked with colored dots.
Performing the mod
STEP 1: Remove the following components
Remove the RGB resistors to ground
- R073
- R072
- R076
STEP 2: Connect RGBs, Blanking and Audio
Connect the RED, GREEN, BLUE, BLANKING wires 
Connect the SIGNAL, AUDIO RIGHT, AUDIO LEFT, GROUND wires 
Overall mod 
STEP 3: Build your mux circuit
Below mod uses the RGB mux board. This is optional, but will make your mod easier and stable. You can also create the circuit presented in the schematics above without the board. Please also checkout the precalculated resistor values.
| Configuration | AT2408 |
|---|---|
| RGB termination (R1, R2, R3) | 75Ω |
| RGB inline resistors (R4, R5, R6) | 220Ω |
| Audio Left and Right (R7, R8) | 1kΩ |
| Blanking diode (R9) | 1N4148 |
| Blanking Resistor (R11) | 1kΩ |
What you see below is the earlier version of the mux board. Newer v1.3B RGB mini board should work well for this mod.
STEP 4: Attach the female SCART connector to TV
Creating a SCART cutout and mounting it is an art. I have a dedicated section for it.
How to create and mount a SCART female plug?
Pictures
