Sony (BA-2) KV-20S10

# Sony (BA-2) KV-20S10 CRT RGB mod

The Sony Trinitron KV-20S10 is a 20" curved CRT television released in 1994, featuring the BA-2 chassis. Renowned for its classic, boxy 90s aesthetic, this model is highly sought after due to its compact size, RGB moddability, sharp picture quality, and excellent 2D scrolling geometry.

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

This Trinitron model used a single chassis design and featured built-in stereo speakers, along with one composite video input and an RF input on the rear panel. It also included a single headphone jack on the front. Performing an RGB modification on this set was both worthwhile and relatively straightforward, as it already contained an unused analog RGB input that could be easily repurposed.

The RGB image exhibited a slight underscan that was not present when using the composite input. Although most of the capacitors tested within specification, some showed minor ESR drift. I reflowed the entire chassis and replaced several electrolytic capacitors, but neither of these measures resolved the RGB underscan issue. They did, however, noticeably improve the overall image quality.

This experience reinforced an important lesson: a blind recap is not always the solution. Proper diagnosis requires the use of an oscilloscope and careful signal measurements to identify the root cause. In addition to electrolytic capacitors, other components can drift out of specification over time, including film capacitors and resistors.

# Contributors

Thank you to everyone who contributed to this guide:

• Eli Krauseopen in new window — contributor, CRT specs from CRT Database.
• Suntharopen in new window — contributor, RGB mod and pictures

# CRT safety

READ THIS BEFORE CONTINUING

# Plan of attack

READ THIS TO PREPARE

# Manuals and Datasheets

• SONY KV-20S10 SMopen in new window
• Sony CXA1465AS Datasheet (Jungle)open in new window

# Specs

• Manufactured: Mexico (1994)
• Format: NTSC
• Chassis: BA-2
• Tube: Sony Trinitron A51LDG50X
• Jungle Chip: Sony CXA1465AS
• OSD Chip: M37265M4
• Screen Size: 20"
• Inputs: Composite, RF

# Schematics

# RGB mux diagram

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

# Performing the mod

You can't ask for a more straightforward RGB mod.

Fortunately this chassis doesn't require any muxing. You can pass R, G, B through a 0.1uF, 75ohm terminated wire directly to the chroma IC301. Blanking (Ys) can be fed through a 1kΩ + 0.7V didoe to pin 15 of the chroma.

# STEP 1: Free the RGB inputs

• Remove the R325 ground resistor (10kΩ) from the board.
• Carefully cut the traces on the board to ensure that the R, G, and B traces are no longer connected or shorted together.
• Make sure R, G and B are not connected to the ground either.

Cutting traces is the best approach and can be easily reversed back if needed.

# STEP 2: Connect RGB wires

See picture below to see where R, G, B wires should be connected. They are connected directly to the chroma IC. Red, Green, Blue lines are exposed on chroma pin 16, 17, 18 respectively. Since the gap here is really small, take care when soldering the wires.

# STEP 3: Connect blanking

See picture below and reference the mux diagram above to connect the blanking. Inductor leg closer to the OSD was lifted and a diode was added (pay attention to where the stripe is pointing). Blanking was then injected in the middle.

# STEP 4: Connect Sync, Audio and Ground

Sony KV-20S10 supports stereo. Therefore, audio left and audio right were wired as below. Suppose your BA-2 board only supports mono, you can twist both audio left and right and connect it to the mono audio input. 1 KkΩ audio resistors on the mux board will ensure right and left channels are mixed properly.

Sync wire (yellow) should be connected directly to the composite input.

Black wire is the common ground wire. With the latest 1.2B/1.2C PCB design you can leave both purple and orange wires floating or connect them to ground.

# STEP 5: Build your mux board (using the micro RGB 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
• RGB MUX BOARD KIT 1.3Copen in new window

Buy your RGB mux board kit

Buy your RGB mux board with the necessary parts to complete this modopen in new window

# STEP 6: Attach the female SCART connector to TV

I decided to mount the SCART connector on the top part of the input cavity.

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?

# Service Menu

On the remote, press keys in this sequence DISPLAY, 5, VOL +, POWER

1 and 4 to select 3 and 6 to adjust

MUTING, ENTER to write to memory.

# Mux overlay

# Games

# Patterns

RGB Grid

Composite Grid

RGB SMPTE

Composite SMPTE

RGB Colors

# Set

Tube - A51JUH51X

Full Chassis

Neck Board

Chroma

OSD

Flyback

Open Back

# Capacitors

# Service Menu Settings

# Pictures

# Reference Photos

See more photos and contributions →open in new window