TFT Display not working with the PI Zero W

[PiLie]

Hello, i have a faulty raspberry pi zero w which bluetooth and wifi isnt working. Now i have found that whatever i do, i can't get to make the TFT monitor work properly from its TV jumpers. I've connected it right and edited the /boot/config.txt file. I also have a raspberry pi 2 B and the screen works perfectly on that one. i have this screen: "http://www.ebay.com/itm/4-3-TFT-LCD-Car ... 2749.l2649". I was hoping to get some help and maybe is there a program on the RPI that i can install and run the tft display? and could it be that if my Network chip doesn't work i can't get the screen to work either?
Thank you,
Paul.

[drgeoff]

What OS and version? A card that has an old version can work OK on a RPi2 but not be recent enough to properly support a ZeroW.

With a default installation of Raspbian or NOOBS you should not need to edit config.txt to have the composite output working. Just boot without HDMI plugged in.

Are you certain you have correctly identified the grpund and video points on the ZeroW?

[PiLie]

I am running the latest version of Raspbian and i have just reinstalled the SD card and updated it, because i was full on stuff and i wanted to reset my config.txt file. I have tried to run the PI with nothing, but the TFT display attached to it, but that didn't work. My connections are right, unless you need to attach the video input to ground (which i don't think so, but i don't know). If it doesnt send the video in the start is there a way to just force it in the display or try to connect the display to the GPIO's ?( but not TX or RX, because i'm using them for a project). My display does not start if the display signal is not given to it and maybe the RPI doesn't detect the screen because its off in the beginning and thats why it doesn't send the signal to it, because it thinks there is nothing attached to it, so i'd like to find a way to just send the signal no matter what happens if i can.

[PiGraham]

Useful guide here
https://www.modmypi.com/blog/how-to-add ... ry-pi-zero

sudo nano /boot/config.txt
There are two lines you need to edit.
First, you need to REMOVE the comment # from the line
#sdtv_mode=2
So it should look like this:
sdtv_mode=2
Next, you need to ADD a comment # to the line
hdmi_force_hotplug=1
So it should look like this:
#hdmi_force_hotplug=1

[PiLie]

I have tried that, it did not work and i think the reason why it didn't work is because the display doesn't have an on off switch, so it turns on when it receives an input signal and the raspberry pi (i think) checks if there is a display attached to it before it sends the signal to the display and the Pi thinks there is no display attached (because it was off by default) so it does not send out the signal to the display.

[drgeoff]

I have tried that, it did not work and i think the reason why it didn't work is because the display doesn't have an on off switch, so it turns on when it receives an input signal and the raspberry pi (i think) checks if there is a display attached to it before it sends the signal to the display and the Pi thinks there is no display attached (because it was off by default) so it does not send out the signal to the display.

RPis DO NOT sense if anything is connected to the composite output.

You should connect both holes/jumpers on a Zero(W) to the composite video input of a display. Video is the square pad. Ground is the round pad (beside the 4R7 coil).

[PiLie]

So, i guess my theory was wrong about the pi sensing if its attached, but i have checked and i have connected it right, but still no luck, because the display doesn't light up. The display is working, because if i connect it to the Pi 2 it shows life and works perfectly.

[PiLie]

could it be that my /boot/config.txt file doesn't run when the pi is booted? or no, because my HDMI is working, is there any way to check or run it manually?

[drgeoff]

It is quite simple:

1 . Micro-SD card with fresh install of Raspbian image. NO changes to any files.

2. Connect HDMI monitor and power up the ZeroW. Does it boot and display on the HDMI monitor?

3. If yes, shutdown the ZeroW and remove power.

4. Unplug HDMI monitor. Attach composite display.

5. Power up ZeroW and display.

6. If it does not display there are only 4 possibilities.
6.1 Wrong or badly wired connection to the TV holes on the ZeroW
6.2 Faulty cable to the composite monitor
6.3 Faulty composite display
6.4 Kaput video output on ZeroW SoC. Given that the Wi-Fi and Bluetooth don't appear to be working ......

[PiLie]

ok, got it, but it might be a few of them, because i have mixed the polarity of the display power wires and don't know if it still works and i might have fried the composite output, but i will try it. thanks

[PiLie]

OK, it might be the Raspberry pi, because i have tested the display and it works perfectly with PI 1 B, but it still does not work with the zero w. I am guessing that it might be the pi that has a bad composite output, because i have done how you said, i have reinstalled the raspbian again and it didn't work.