DIY - Tear Down and Inverting the LCD Screen on a Continental TR7412UB-OR

[thatsagiven]

[bmwman91]

Nice work!

[Northern]

This makes me want one of these head units. How well does the bluetooth work?

[thatsagiven]

Northern Bluetooth works well, but the downside is that is wont show the album and song title. When playing it only shows A2DP on the screen. Calls are good, and bt playbook is good, quick to connect and overall as good a Bluetooth experience as the clarion deck except for the song titles.

[roguetoaster]

Northern Bluetooth works well, but the downside is that is wont show the album and song title. When playing it only shows A2DP on the screen. Calls are good, and bt playbook is good, quick to connect and overall as good a Bluetooth experience as the clarion deck except for the song titles.

Yes, the implementation is odd, but the BT and mic are both good, with the mic even working well enough for brief communications with windows down.

Good job OP!

[bmwman91]

Hey, so I ordered up a TRD7412UB-OR (the "D" variant which has DAB, not that it is of any use in the US, but it also allows for backlight brightness control which is very handy). thatsagiven can you explain a little more about the inversion of the polarizer? Did you just flip it over along its long (or short) direction, or rotate it 180° without flipping it?

I am probably going to swap out all of the backlight LEDs with 605nm orange ones (have done this with multiple aftermarket radios in the past, and it makes for a perfect match with the interior). When I do it I will document it on here. I will also look into flush-mounting it, which may require some 3D printed brackets and stuff, but I guess that I can live with a ~1/4" protrusion if necessary.

[earthwormjim]

@bmwman91, you buy a new 90 degree polarizing filter, and rotate it (not flip) 90 degrees relative to how the old 90 degree top filter was installed.

Flipping won't do anything, light can pass through the filter the same on either side.

I realize I'm saying 90 degrees multiple times, but polarizing filters come in degree ratings, based on what alignment of light they allow to pass. So you want a 90 degree polarizing filter, AND you want to install this filter such that it is also rotated 90 degrees relative to how the original top filter was installed.

If you're unsure which direction is 90 degrees relative to the old filter, you can use the old filter to test. After you peal the old filter off, lay it on top of the new filter sheet. If both are orientated in the same direction (what you do not want), you will be able to see through them. If the new filter is rotated 90 degrees (this is what you want), you won't be able to see through both filters.

It's the same process as shown here:
https://www.watchuseek.com/threads/h...isplay.129102/

The reason why this works is that the LCD display actually has two polarizing filters. A bottom one, behind the actual liquid crystal element, but in front of the backlight, and a top filter, the one you will be replacing.

The bottom filter only allows light from the backlight to pass that is already in alignment with its 90 degree twist, creating a 90 degree polarized beam of light. Wherever the liquid crystal is displaying text, it rotates (not just filters) the light by 90 degrees. Wherever there is no text, the light passes through the liquid crystal display unchanged. We are incapable of distinguishing light polarization, so without a top filter, you would not see anything other than the backlight.

With the top filter in place with the same alignment as the bottom filter, you will see dark wherever the LCD has twisted the light (text), and bright wherever the LCD has not twisted the light (background).

With the top filter in place with its alignment 90 degrees relative to the bottom filter, you will see bright wherever the LCD has twisted the light, and dark wherever the LCD has not twisted the light.

When inverting, you could theoretically replace the bottom filter rather than the top filter. The only issue is accessing it. You would either have to bend the connecting pins or desolder the display from the board. Might end up with a better looking result, since you preserve the original top filter, which seems to look better during the day, than any of the 3rd party filters I've bought. But looks much harder to do.

[earthwormjim]

FYI, you do not need to break the warranty seal to remove the display front panel. There's plenty of length on the ribbon cable to unplug it after you unscrew the side screws and unclip the front panel.

[bmwman91]

FYI, you do not need to break the warranty seal to remove the display front panel. There's plenty of length on the ribbon cable to unplug it after you unscrew the side screws and unclip the front panel.

Awesome, thanks for the info! This will definitely make life easier when I get the radio.

[varg]

This is very cool. Thanks for sharing. The only thing that stopped me from buying one of those head units was that it had no RCA subwoofer output, so I wound up putting a KDC-BT378U in the wagon which does not look as good as that continental but at least it has variable display and button color so it matches well.