Samsung TXD1973 CRT RGB mod
This tutorial covers the RGB mod for the Samsung TXD1973 CRT TV.
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.
Plan of attack
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.
- Manufactured: 1997 October, TIJUANA, MX
- NTSC, 60 Hz, 80 Watts
- Chassis: K1
- Tube: Samsung A48KRD82X (This tube was used in swapping K4600 tube)
It's hard to find the service manual for this Samsung CRT TV. I had to stitch together this scehmatic diagram from multiple images. Although not perfect, this should be sufficient to perform the RGB mod.
Prototyping the mod
Since this is the first time I'm modding a CRT from Samsung, I wanted to prototype the mod first. I reviewed the schematics and came up with the below plan.
The main board is fairly compact. The main board also comes off the CRT completely, if all the wires are carefully disconnected. This makes it easier to perform the mod. Please make sure to remember or take photos as you disassemble, so that you can reassemble the way it was prior to disassembly.
Simplified circuit diagram that was created to perform this mod. Check the RGB theory page to find more details around how to calculate the resistor values.
Performing the mod
This CRT was fairly straightforward to mod. You can perform the mod on the board itself and don't need a MUX board.
Using the stock SCART port
This CRT comes with a stock AV port that has a SCART cutout. I wanted to utilize this to give this CRT a clean look. Here is how it looks when finished.
You will soon realize this is not as easy as it looks. There isn't that much space on the board to accomodate a SCART plug and the necessary wiring.
How was this achieved?
Remove the existing A/V connector.
Move some of the components to the bottom of the board to make some space.
Create a flexible pcb that grouned the relevant pins together and allowed for routing of the wires. Flexible pcb was used, because there is not much clearance and you want this to be flexible. I'll let the pictures below explain the process.
Check the placement of the flex pcb
Make your own flex ribbon board at OSHPark or buy it here
Attach all the necessary wires
Flush cut the SCART pins and solder to the flexible pcb.
Insulate the SCART adapter with some electrical tape
Insulate the main chassis
SCART side view
Removed R204, R205, R206. Used the existing vias to connect R, G, B, blanking and ground.
- R, G, B (red, green, blue wires)
- Fast Blanking (brown wire)
- Ground (black and purple wire)
- Ground (leave the organge wire disconnected)
- CSYNC - directly connect the CSYNC pin to the board and solder it.
RGB wires needs a triangle formed between 75 ohms and 1.2 kohms. 75 ohms goes to the grounding side. 1.2kohms faces the 0.1uF capacitors.
Blanking wire (brown) needs a didoe inline. Replace the existing blanking inline resistor with another diode and put a 6.8 kohm resistor after the diode.
Bypass the CCD to ensure the video is not dark
Audio wiring (grey, white). Put two 1 kohm resistors for both left and right wires and connect them both to the board
Ground wiring (black, purple). Twist them together and connect them to the below location.
Connect CSYNC to this location
Use heat shrink tubes to prevent shorting.
All wired up!
How the back of the TV looks after buttoning everything up.
Connector will be a bit wobbly. However, once the back cover is put back in place and closed up with screws, connector should stay strong. Please be mindful not to push the connector in too tightly and break the connector. Understand the limitations of this mod and possibly use an extension not to damage the SCART connector. SCART closeup. Back cover holds connector in place.
Adjustments, Games and Patterns
Colors don't really pop on this TV for some reason. But, it has a nice overall look that will give an awesome nostalgic experience. Modding this TV is really straightforward. Image was a bit washed out, right after injecting the RGB signal without touching anything on the CRT.
Let's see what options we have to make this look better.
Adjusting the flyback screen brightness
After decreasing the
screen brightness on flyback, colors seemed to be much better. OSD menu overlay was also visible.
Standby mode, using the remote
POWER should bring you to the service menu.
Default settings for this CRT
HS - Horizontal Shift was adjusted to center the RGB image. RC - Red Cutoff and GC - Green Cutoff was adjusted to
21 respectively to reduce the redness and balance the colors. YMMV.
Super Mario World SNES
There are quite a few prominent folks who pioneered RGB mod on this TV. Links to their content below