Toshiba 27A35

# Toshiba 27A35 CRT RGB mod

The Toshiba 27A35 is a 27" curved CRT television released in 2005, with the last digit of the model number indicating the release year.

The curved CRT screen delivers excellent geometry and sharp picture quality. This television features component video inputs and allows users to monitor the number of hours the tube has been in use, provided the counter has not been reset. The 27A35 offers superior geometry and reduced distortion compared to flat-screen alternatives and is RGB modifiable.

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

This is similar to Toshiba 27A34, but the location of jumpers and resistors removed etc. are all different. I also chose to permanently set this up for stereo, so that no dummy plugs are needed. I'm fairly impressed with this Toshiba compared to JVC D-Series and several 27" flat Trinitrons that fail to deliver similar convergence, geometry and lineraity. Horizontal linearity and scroll was amazing on this tube.

# Table of Contents

# Contributors

Thank you to everyone who contributed to this guide:

• Suntharopen in new window — author, RGB mod and pictures

# CRT safety

READ THIS BEFORE CONTINUING

# Plan of attack

READ THIS TO PREPARE

# Manuals and Datasheets

• TOSHIBA 27A35C SMopen in new window
• Renesas M61283BFP Datasheet (Jungle)open in new window

# Specs

• Manufactured: Thailand (2005)
• Chassis: M3U525
• Tube: Orion M68LWF088X50
• Jungle Chip: Renesas M61283BFP
• OSD Chip: Orion OEC7090B
• Screen Size: 27"
• Power: 125 W
• Inputs: RF, Component YPbPr, Composite, S-Video

# Chassis

# Schematics

Get hold of the schematics/service manuals for your TV. Understand where the RGB and Fast Blanking signals go from OSD to the Jungle (Chroma) chip.

# RGB mux diagram

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

# Performing the mod

We will be focusing on the following area for the RGB mod.

• Area A is where the RGB and blanking wires will be installed
• Area B is where the audio, sync and groud wires will be installed.

# STEP 1: Remove the grounding resistors and capacitors

We are performing an interference supressing mod. Therefore, it is a bit more involved. We are going to remove the three 820Ω RGB ground resistors and the 3 stock 0.1uF capactiors.

Remove

• R141
• R142
• R143

Remove and short (see pictures)

• C136
• C137
• C138

OSD grounding resistors R141, R142, and R143 should be removed. The inline capacitors C136, C137, and C138 should be removed and replaced with small jumpers.

# STEP 2: Remove jumpers

Remove the following jumpers. Jumper naming is hard to read on the chassis. Just use the picture as a referene to remove the the jumpers.

• W108
• W110
• W111

Where we expect the R, G, B and blanking wires to go. Don't remove jumper W052.

# STEP 3: Replace jumpers with capacitors and diodes

Replace the removed jumpers with 1N4148 diodes and 0.1uF ceramic capacitors, ensuring they are installed in the correct orientation. Pay close attention to the direction of the diodes, as placing them incorrectly will prevent the modification from working. The stripe on the diode must face the right direction.

Picture below illustrates the direction of these components as well as where the RGB lines should be connected. Pay attention to the direction of the diodes. The blanking wire (brown) should be connected to jumper W052.

# STEP 4: Connect RGB and blanking wires

Make sure the wires are installed in-between the diodes and capacitors similar to the picture below.

# STEP 5: Connect sync, ground, and audio

Inject the sync signal into the Component Luma (Y) input, and connect the audio to its corresponding audio lines. Refer to the attached photo for the correct connection points. Additionally, cut the trace as indicated to permanently enable stereo audio and avoid the use of dummy plug. If you do not cut this trace, you'll need to have something plugged into the red RCA audio port (right audio) for stereo to function.

# STEP 6: Build your mux circuit

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

# STEP 7: 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?

# Muxed OSD over RGB

# Games

# Patterns

# Set

Back open

Flyback

Cathode Glow

Neck board

Speaker

Tuner

Anode cap

# Where this set was found?

# Pictures

# Reference Photos

See more photos and contributions →open in new window