Sony (BA-5) KV-20FV12

# Sony (BA-5) KV-20FV12 CRT RGB mod

The Sony KV-20FV12 is a 20" Flat Trinitron WEGA CRT TV known for superior 240p/480i picture quality. Released around 2002–2003, this flat-screen set features S-Video/composite inputs.

This set can be modified for RGB input.

View full CRT details and more mod examples →open in new window

# Contributors

Thank you to everyone who contributed to this guide:

• Dan Lavoieopen in new window — showcase author
• Wei Linopen in new window — showcase author
• Mike Morisetteopen in new window — contributor, CRT specs from CRT Database.

# CRT safety

READ THIS BEFORE CONTINUING

# Plan of attack

READ THIS TO PREPARE

# Manuals and Datasheets

• Sony KV-20FV12 Service Manualopen in new window

# Specs

• Year: 2000
• Format: NTSC
• Chassis: BA-5
• Tube: Sony Trinitron A51LPT70X
• Jungle Chip: Sony CXA2131AS
• OSD Chip: M37273MF-258SP
• Screen Size: 20"
• Inputs: Composite, S-Video, RF

# Schematics

Please note there is a second RGB input available in CXA2131CS. However, it is disabled in softwareopen in new window. You can activate it by using I2C as documneted hereopen in new window. However, it is more effort than just doing a mux mod.

# Calculating the RGB external resistor value

Formula from our theory page!

RGB external resistor value = 0.7 x (6800 + 75) - (75 x 5) / (5 - 0.7) = (4812 - 375) / 4.3 = 1030 ohm

~ 1 Kohm resistors should do the job.

# RGB mux diagram

Prepare the mux diagram. If you are building your own circuit, this diagram should help.

# 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.

# STEP 1: Remove the following components

Remove the following components. RGB resistors to the ground. Measure twice and mark before you remove.

• R1084 (680Ω)
• R1085 (680Ω)
• R1086 (680Ω)

Note: there can be slight differences in the board layout. I have seen slightly different MB board layout, even within the same 20FV12 CRTs.

# STEP 2: Connect RGBs, Blanking and Audio

See picture above to see where blanking should be connected.

Let's remove the jumpers JW1335, JW1336, JW1337 and replace with 3 1N4148 diodes. Pay attention to the direction of the diodes. There is a black bar indicating which way the current flows. This helps reduce feedback noise and voltage going back into the OSD.

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

Twist the orange and yellow wires. Sync wire (yellow) should be connected directly to the s-video Y pin. Ground wire (orange) should be connected to the ground. Audio wiring can go below the board. Connect audio left (white) and audio right (grey) as seen in the pics below.

Ground both common ground (black) and audio ground (purple) wires.

# STEP 2: Special instructions for KV-20FS12

Since there is no s-video you can tap into, try feeding sync to the negative leg of C1385 capacitor. That is the COMB Y input.

# STEP 3: Build your mux board

This 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 mux calculatoropen in new window to play with your own values.

Compatible mux boards:

• RGB MUX BOARD KIT 1.4Copen in new window
• RGB MUX BOARD KIT 1.4Bopen in new window

Buy your RGB mux board kit

It is recommended to use the variant C mini board for this CRT with the straight SCART connector. Variant B board can be used, if the spacing is carefully planned.

# 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?

# 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

# Mux and OSD

Volume

Menu

# Games

NES - Adventure Island

SEGA Genesis - Sonic

SNES - Contra

SNES - Alien

XBOX - UnleashX

PS1 - Boot

# Patterns

SMPTE - Colors

Grid

Monoscope

# Inside of the CRT

Gut of the CRT (comes off completely). Main chassis, MB board, Neck board

Tube and speakers

Neck board

# Pictures

# Photos by Dan Lavoieopen in new window

RGB modification showcase converted from a community support request.

# Photos by Wei Linopen in new window

In this RGB modification project, a Sony KV-20FV12 CRT television was enhanced using a Rev 1.4B mini RGB mux kit.

# Reference Photos

See more photos and contributions →open in new window