# Toshiba 20AF43+ CRT RGB mod

This tutorial covers the RGB mod for the below models.

  • Toshiba 20AF43
  • Toshiba 20AF44
  • Toshiba 20AF45
  • Toshiba 20AF46

Please also see other Toshiba AF series mods, as the instructions are more or less the same.

# CRT safety

DANGER

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.

READ THIS BEFORE CONTINUING

# Plan of attack

READ THIS TO PREPARE

# Service manuals

# 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.

# 20AF43/20AF44

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# 20AF45/20AF46

The biggest difference between 20AF44 vs 20AF45 is there is no VM circuitry (the one that is used for edge enhancements). Therefore, D107, D108 and D110 are missing from this schematics.

img

# PCB

# 20AF43/20AF44/20AF45/20AF46

Points where the R, G, B and Blank wires should be connected are marked "X". Pink boxes show the resistors, diodes that needs to be removed.

Actual PCB might be slightly different for 20AF45 and 20AF46. However, the mod that needs to be applied is in similar location.

img

# Performing the mod

# STEP 1: Remove the following components

# 20AF43/20AF44

Remove the RGB resistors to ground

  • R141
  • R142
  • R143

There were no coupling capacitors to ground that needed to be removed

Did not remove C131 or C135. Removing them can affect the background of the OSD.

Unplug the VM cable on the neck board. img

(Optional) Remove diodes that enable VM from the RGB lines.

  • D107
  • D108
  • D110

# 20AF45/20AF46

Remove the RGB resistors to ground

  • R141
  • R142
  • R143

No diodes to remove on this board. There are no cables to unplug on the neck board.

# STEP 2: Connect RGBs, Blanking and Audio

# 20AF43/20AF44/20AF45/20AF46

Connect the RED, GREEN, BLUE, BLANKING wires img

Connect the SIGNAL, AUDIO RIGHT, AUDIO LEFT, GROUND wires img

# 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.

Buy your RGB mux board

Depending on the RGB/OSD stock resistors your CRT has, use the below inline resistors.

TV Model 20AF4x 20AF4x 20AF4x
RGB/OSD stock resistors 3.3kΩ 3.9kΩ 6.8kΩ
Audio LR (R7, R8) 1kΩ 1kΩ 1kΩ
RGB termination (R1, R2, R3) 75Ω 75Ω 75Ω
RGB inline resistors (R4, R5, R6) 470Ω 560Ω 1kΩ
Diode (R9) 1N4148 1N4148 1N4148
Blanking Resistor (R11) shorted shorted shorted

Sample Toshiba 20AF44 RGB Mux Adapter img

# 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

# Mux board on TV

img img img

# Finished mod

img img

Yes, screws are missing. They were put in later!

# Test patterns

Not the best image quality. But, looks pretty decent for a flat CRT TV.

img img

# Games

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