7" touch screen will not function.

Not sure I'm in the correct section but here it is. I have a 7" touch screen that I tried to use with a Raspberry Pi 2B. the touchscreen does not want to power up (I assume this because there is no backlight?) I do have 5V and ground attached from the GPIO and i verified with a scope that i have the proper voltage. i do have various voltages on the display board on the touch screen. I have downloaded the latest Rasbian software and installed. I have turned on the SPI in the Raspberry Pi Configuration screen. so my question is: is this a fault with the touch screen or a software issue? the Raspberry works fine when connected to the HDMI and a TV. I even tried to put power to the power connector via a micro USB, still nothing.

0 clem57 over 8 years ago

Try these instructions https://cdn.sparkfun.com/datasheets/Dev/RaspberryPi/how_to_assemble_the_rpi_touchscreen_display.jpg
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0 Former Member over 8 years ago in reply to clem57

Hi, thanks for your quick response. I have done all these things and verified what you have sent me was consistent with what I found online. Question: is there a back light to this device? Because I am getting no activity at all from the display. I also tried removing the existing keyboard and mouse but still did not activate the screen. Anything I can test?
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0 shabaz over 8 years ago in reply to Former Member

Hi Hank,

There is a backlight, and it is controlled by the Pi. Could you also examine the instructions here: Raspberry Pi 7” Capacitive Touch Display: Assembly and Enclosure
(from the section 'Assembling the LCD Panel Interface Board and Pi', there is slightly more detail, and some of the steps are more critical than some other sites mention), just to confirm everything is correct physically. A slight misalignment of the ribbon cable for instance, or inserted with the insulated side face against the contact strips will of course render it inoperable (not saying that you will have done this, this is just an
example of things which are unclear from some instructions I've seen).

If you have a recent software image then the board should just work with no configuration changes needed from memory. The Pi's Raspbian image knows the display is connected because of a configuration ROM, and therefore the software self-configures.

The HDMI connection I think ought to be disconnected before the Pi is powered up (because the desktop can only appear on one display, the other one then only becomes usable by certain specific software).
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