Internal VGA to LVDS Display Mod

[bench]

I've been wanting to IPS swap 90's Thinkpad models for a while now due to many reasons such as availability, vinegar syndrome, and the original panels not being very good. There are many available 4:3 IPS models such as the 10.4" XGA HT10X21 around $15 and 12.1" XGA HT12X21 around $40. It seems insane to me that someone would spend over $100 on an original DSTN or TFT panel when these IPS panels are cheaper and better.

My original thought was to convert parallel RGB to LVDS using something like the TI DS90C365A for 6-bit displays or DS90C385A for 8-bit displays. By designing a custom flex cable with attached display connectors, a near drop in replacement could be designed with the exception of needing to pull voltage from before the inverter to power LED backlit displays (and to regulate the voltage). This solution seems very good for certain machines, however it has a few big limitations. Without a BIOS mod, these machines are required to have an identical resolution screen swapped in as the original, severely limiting the selection of displays. It is possible to use a scaler to exactly 2x or 3x the resolution, opening the possibility to swap QXGA iPad screens into XGA laptops, however this would likely need to be FPGA based and fairly expensive (OSSC has good documentation on this). To keep it simple, I bought a Kyocera TCG104SVLQJPNN-AN40 which is a 1200 nit 10.4" SVGA IPS LED panel to swap into my 10.4" SVGA Thinkpad 365XD. As I was planning to route the 24 parallel RGB colors, HSync, VSync, DE, and power into the TI chip to convert into LVDS, I realized that designing all this would be exclusive to the 365XD and related models. I also realized that I just spent $100 on a SVGA display panel when a $15 XGA panel exists (despite being CCFL). If I could just pull the RGBHV pins from the VGA port, bring them up to the display, and convert them to LVDS, then I would be able to make a universal board that works in any laptop with a VGA port, as well as allowing me to use just about any resolution display I want.

So now I ordered the cheapest VGA to LVDS adapter I could find on Aliexpress. In this case, cheap means simple which means small which means good. The dimensions are 108mm x 35mm but I'm not sure the thickness after removing the ports. The adapter is based on the Realtek RTD2270 which requires an external flash ROM for EDID, but not much else for converting signal since the IC handles the ADC and sync processing. This board can likely be trimmed down a lot since it has an inverter and input voltage regulator. If this works well, I may design a custom PCB to reduce the size even smaller and add pads to clearly label input and output.

This is where I'm at now with the mod. I will keep you guys updated once the board arrives.

[astral]

I can't wait to hear more from this project! Finding space inside the laptop to mount the board shouldn't be that difficult - if you replace the hard disk with an SD card in an adapter, you'll have most of the bay freed up.

[panips]

Cable organization is challenging and you might need to remove the battery to free up space.
If the LCD screen has a noisy display, switch to a twisted pair cable for the signal.

[bench]

Interesting setup, do you have more details about your mod? I looked into it and couldn't find any info about it, but figured that someone on the 51nb forums probably did it before.

For my setup, I was planning on fitting the adapter in the screen assembly since there is so much free space and modern panels are much thinner. I would still have to desolder the ports on the board but the original 365XD display is something like 12mm thick. This does make interference worse from VGA but it means I'm running only 6 wires to the display, which I plan to shield anyways.

[blegas78]

Love this project idea! I have a QXGA iPad display sitting around and would love to retrofit it into my 760xd XGA (barring a size mismatch of 9.7” vs 12.1”).

You mentioned the parallel RGB (DPI?) pins from the Thinkpad, do you have pinouts for some Thinkpad models?

[panips]

Interesting setup, do you have more details about your mod? I looked into it and couldn't find any info about it, but figured that someone on the 51nb forums probably did it before.

For my setup, I was planning on fitting the adapter in the screen assembly since there is so much free space and modern panels are much thinner. I would still have to desolder the ports on the board but the original 365XD display is something like 12mm thick. This does make interference worse from VGA but it means I'm running only 6 wires to the display, which I plan to shield anyways.

No more pictures now (gifted...), but I'm sure it was quite straight forward, just lots of soldering work, which I never want to do it again.
Maybe good for reviving some old stn/dstn ones, but basically I do not really like that. It's weird -- too bright, lagging of displaying when booting up, and lacking the vintage taste and memory.