Sony KV (BA-4D) 20S42 RGB

# Sony KV-20S42 RGB mod

The RGB mod for the Sony KV-20S42 is fairly simple and makes a noticeable improvement on this composite-only set. Additionally, the KV-20S42 can be modified for component input as well. For this mod, I also decided to permanently enable stereo sound. Interestingly, it's possible to add an S-Video input if you can find the right connector, though I plan to tackle that at a later time. You can also follow this older tutorial which has additional pictures.

Instructions below should also apply to these models:

• KV-13M42
• KV-20M42
• KV-20S42
• KV-20S43
• KV-20S90
• KV-27S42
• KV-27V42
• KV-27S46
• KV-27S66
• KV-35S36

# CRT safety

READ THIS BEFORE CONTINUING

# Plan of attack

READ THIS TO PREPARE

# Theory

Sometimes it is nice to know the theory behind the mod. I have put this on a separate page. This shows how the various resistor values are calculated.

READ THE RGB MODDING THEORY

# Service manuals

• Sony KV-20S42 Service Manual

# Specs

# Sony KV-20S42

• Manufactured: September 1999, Mexico
• NTSC, 60 Hz - 90W
• Chassis: BA-4D
• Tube: A51LML50X
• Jungle Chip: CXA2133S/CXA2133BS
• OSD Chip: M37273MF-255SP

# Schematics

# Performing the mod

Now that you roughly know what needs to be done, prepare for the mod. Place the board on a comfortable place. Make sure you are not putting pressure on the flyback or other components. Taking out the chassis is fairly straight forward on this CRT.

There are few wires that needs to be disconnected.

1. Degauss wire
2. Power wire
3. Ground wire attached to the neck board
4. Yoke deflection coil wire
5. Anode wire (this is the one with the rubber cap)
6. Left and right audio wires

Please remember that wires 1-5 are critical for the CRT to function and should not be omitted. Having any of these wires disconnected while powering up can damage the board and can have adverse effects.

Sometimes it can be overwhelming to see a large chassis. But, we are primarily going to focus on two areas.

• Area A: This is where we are going to remove resistors and attach the R, G, B and blanking wires
• Area B: This is where we are going to connect composite, audio L, R and ground wires

# STEP 1: Add RGB inline diodes

I recommend using this method for all KV-20S42 mods to minimize interference. You'll need to lift one side of resistors R025, R026, and R027, and add diodes. The side of the resistors you lift and the direction of the diodes are crucial. If done incorrectly, the OSD will not function. Be sure to follow the instructions and pictures provided carefully.

Also, adding didoes means you will need to use 1KΩ resistors on the RGB mux board.

# STEP 2: Remove resistors and attach R, G, B wires

Zooming in on Area A before removing the resistors.

Remove the following components. RGB resistors to the ground. Please always measure and mark them, so that you know you are removing the correct partrs.

• R087 (680Ω)
• R088 (680Ω)
• R089 (680Ω)

Then attach the R, G, B and blanking wires to the respective legs of the diodes. Wires should be attached to the side closer to the jungle chip.

R, G, B wires are red, green and blue respectively Brown wire here is used for blanking

# STEP 3: Permanently enable stereo

This is a relatively new step in the process. I desoldered the RCA connector at the back and removed the physical switch that activates mono audio when the red RCA port is unplugged. An alternative is to cut the trace to isolate the metal clip. However, I prefer the method below since I have a desoldering iron that makes this task much easier.

Clip that enables mono audio is pulled out.

# STEP 4: Connect Sync, Audio and Ground

Wire colors

• Black wires is common ground
• Grey wire is for right audio
• White wire is for left audio
• Yellow wire is for sync
• Orange and purple wires are auxillary and can be tied away for future use.

# STEP 5: Build your mux board

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

# STEP 6: 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?

Depending on your CRT, you might need to find a good place to mount the SCART port.

# Getting into the service menu

• Turn the set on and then put into standby
• Press the Display, 5, VOL + buttons in sequence
• Turn on the CRT and you should be in service mode
• Use buttons "1" and "4" on the remote control to navigate the service menu
• Use buttons "3" and "6" to adjust the selected data

# Pictures of the mod

# OSD mux mod

# Games

SNES - Metroid

SNES - Super Mario World

SNES - Yoshi's Island

NES - Adventure Island

PS1 - Boot

XBOX

# Patterns

Grid

# Set Pictures