Android Head Unit - LED Colour Change - T7019A (and TUN21A)

[Tech]

The T7019A Android head unit comes with green LED's to illuminate the buttons. This document attempts to show how to change these LED's to better match the red/orange dash lights in the Toyota GT86 or Scion FRS. Of course, they can be changed to any colour if you need a different colour for the BRZ.

This procedure and photos are of the T7019A but is likely to be a very similar procedure for the TUN21A but can't be sure. This is the unit out of the car of @nzer. There is a massive thread including root files etc on the particular head unit here http://www.ft86club.com/forums/showthread.php?t=29723

Actual head unit is:


and is available here
http://www.tradesolution.hk/e/ptxweb...duct/1274.html

Disclaimer:
Unless you have sound electronics knowledge and exceptional soldering skills, I DO NOT recommend you attempt this yourself. There are many potential pitfalls along the way. Every effort has been made to document the procedure, but I accept no responsibility whatsoever for any damage that may occur due to omissions and/or errors contain herein. Proceed at your own risk!

The LED's are a 0603 SMD package. Make sure the parts you purchase are of this footprint or they may not fit correctly. Also choose an LED with an intensity of between 100 and 150mcd anything brighter than this may be too distracting at night. These are the LEDs I used http://tinyurl.com/ma2hyo4



First remove the 6 screws that hold the face plate on. Gently move the faceplate away from the body and you will see a number of ribbon cables that will need to be disconnected before you can separate the faceplate completely from the main head unit chassis.



To release the ribbon cables, use a pair of fine tweezers and gently push the dark brown clamp away from the socket a little at a time, alternating sides. It will only move about 2mm or so. Do not force it beyond this or you risk breaking the clamp which cannot be fixed!

Once the clamp is released the ribbon will come out (or even fall out) easily. Try not to move the ribbon around more than is necessary once released. All of the ribbon cables use the same "type" of socket , just different sizes so the procedure is the same.




Once you have released all the obvious cables, you can separate the front display unit from the main chassis.




Remove the two front knobs. These just pull off. Lay the unit face down and disconnect the two ribbon cables. One on each board.



Unsolder the microphone wires. Note when reconnecting later, that the red wire is soldered to the pad marked +. Remove the screws around each LED board. DO NOT remove the 4 screws that hold the centre board to the metal bracket. Lift up the centre circuit board and metal bracket one side at a time just enough to remove the two boards. Handle the centre circuit board very gently because it is still connected to the front LCD panel. Minimum movement should be all that is required.



There are 17 LED's that need to be changed.



All the LED's are configured as a common cathode arrangement, which means all the "cathodes" of each LED are connected to the ground plane (the large copper area on the boards). The other end of the LED is the "anode" which in each case will have a single track coming off it. This is important, because if you get them around the wrong way, they will not light. However, neither the head unit or LED will be damaged.

For the next step, you are on your own. I cannot teach you how to solder in a document, but as stated earlier, if you don't have the required skills you should not be attempting this in the first place!

Remove each LED carefully so as to not damage the PCB pads. If you have a de-soldering station then I recommend you use a powered solder sucker to remove the old solder from the pads. I DON'T REUSE OLD SOLDER! If you do not have this tool, then you can often wipe most of it off quickly with the tip of the soldering iron. This will get the pad relatively flat ready for the new LED.

Once they have all been removed, lightly tin ONE pad of each LED location. Pick up the new LED with fine tweezers, (noting the correct orientation) and heat the pad you pre-tinned while sliding the LED edge into it. Once in place and flat, solder the other side. Repeat this process for the other 16.

Once all the LED's have been replaced, I connected a variable voltage bench power supply to the boards and wound the voltage up slowly. At around 4V the LED's will begin to light. At 12V they will be at full brightness and with both boards connected, the total current draw should be no more than 300mA. Each LED is in series with it's own 560 ohm resistor. Sorry I did not take any pictures of where I made the power connections for this test. No other part of the unit was powered up!



I know this is a terrible picture, but I wanted to make sure it worked before reassembly and also to compare the old against the new.

Fit the boards back into the face plate and reconnect the ribbon cables. Don't forget to resolder the microphone wires back onto those pads in the correct polarity. Make sure everything sits down nice and flat BEFORE you refit the screws. Nothing should be sticking up or not fitting correctly. Also make sure the USB and SD Card sockets engage properly into the holes behind the trap door. Refer to earlier pictures as necessary.

Reconnect the ribbon cables from the main unit to the headers on the face plate. This can be a bit of a challenge because one of them is very short in length. Make sure they are fully inside the socket and in straight before closing the latch on the socket. This is done by putting firm pressure on the latch and pushing it back towards the socket. Failure to get this right will cause problems like buttons not working or even the touch screen itself. Take your time and be careful this is delicate work! Make sure you have all cables connected.

Secure the faceplate to the main unit with the six screws and then push the two knobs back on. If you are happy with everything, then reconnect the head unit back in the GT86 or Scion FRS and power up. Check all functions before bolting it in permanently or fitting the dash surrounds.

All done!

Again I apologise for the fuzzy picture. My Camera does not focus well in low light, but you can see here that the colour and brightness in my opinion is pretty good.



There should be enough info here as a guide to get the job done, but it is impossible to detail every little thing. Patience, careful handling and common sense are your greatest tools.

Good luck.

@Tech

[nzer]

Thanks @Tech

That all looks way beyond me - I'm glad you did it! :happy0180:

Can't wait to get the unit back off you tomorrow with my new red/orange LEDs.

[Trap63]

Great! During the WE I'll try by myself.......!

[GreenPants]

You forgot to add a link to the source you used for the LEDs.

I'll be putting an order in soon, hopefully.

Update: ordered.

[Tech]

Originally Posted by GreenPants

You forgot to add a link to the source you used for the LEDs.

I'll be putting an order in soon, hopefully.

Update: ordered.

Thanks - link included now in original post but is here:
http://tinyurl.com/ma2hyo4

This is of course is the link to the New Zealand website, but RS Components is worldwide so just log on to the website in your country/area. The part number shown is the same for any RS Component website.

[nzer]

Thanks @Tech - here's the T7019A reinstalled with the LEDs changed - yee hah!

[GreenPants]

@Tech - is the 0603 package size imperial, so the same as 1608 metric? (1.6mm x 0.8mm)

[Tech]

The 0603 is an industry standard SMD package, just like the 0805 and the 1206. However, to answer your question. Yes you will be fine with 1.6mm x 0.8mm which is basically the same thing.

[Tech]

@nzer I see you are playing my all time favourite song by G&N

[GreenPants]

Originally Posted by Tech

The 0603 is an industry standard SMD package, just like the 0805 and the 1206. However, to answer your question. Yes you will be fine with 1.6mm x 0.8mm which is basically the same thing.

Wikipedia seems to imply that there are both metric and imperial standards - I guess the US/imperial standard is simply mentioned more often.

Just wanted to make sure..

Thanks.

[nzer]

Originally Posted by GreenPants

Wikipedia seems to imply that there are both metric and imperial standards - I guess the US/imperial standard is simply mentioned more often.

Just wanted to make sure..

Thanks.

You'll see in my photos @GreenPants that the red kind of matches the hazard switch. I think that is ideal but if you want it to match the clock and HVAC temp colour you may want to go a bit more orange.

Trouble is that oranges can be very orangey and bright and you may end up with it looking worse than the green!

[Trap63]

here the Led Standard....

[GreenPants]

Originally Posted by nzer

You'll see in my photos @GreenPants that the red kind of matches the hazard switch. I think that is ideal but if you want it to match the clock and HVAC temp colour you may want to go a bit more orange.

I've got some of the same LEDs you have on order (640nm), but saw your photo and thought it was perhaps a bit too red for my liking. Given that I haven't started the process I ordered some extra LEDs which should only be slightly more orange (630nm).

We have some different red LEDs at work here that operate at 630nm, and it seems like it should be a reasonable color match. But I'll wait for both sets to arrive and decide then.

[Trap63]

I ordered and just arrived these from Germany (625 nm). With great luck..a friend of mine has the mother that works for a company who manage boards for Audi and VW here in Italy near Turin!!! So...I hope in a superb and fine works!! and a BRZ compliant style!