TFP401 not working

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Chuck0071
 
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TFP401 not working

Post by Chuck0071 »

I was just trying to calibrate my HDMI/DVI Decoder with touch. While in the process of loading the program a puff of smoke came from the decoder board, now I am not getting any display. This display was working on both my Raspberry Pi and Windows system before this happened. I suspect something failed on the board. I have plugged the board and display into both a Windows 7 system and Mac with the same result, the board lights up the green power and blue HDMI LEDs and the red touch LED blinks, but nothing on the display.

My guess is that the decoder board has had a failure and needs to be replaced.
Thanks

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Franklin97355
 
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Re: TFP401 not working

Post by Franklin97355 »

Could you post closeups of the bad component and the board? Also what were you using to power it when this happened?

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

I have a picture of the decoder board, but really nothing to see on it. There is no visible damage to either the decoder or display, the display just stopped working after I saw the puff of smoke. I was able to calibrate the decoder board on a second try even with out the display working, so the touch sensor circuits are working. I am now thinking the power regulator on the display circuit may be gone. I have test equipment to look at this, VOM and scope if someone can point me to a schematic for the display.

The decoder and display were being powered by the USB cable that connects to the decoder when this happened. Initially the display was working, then the smoke and the display went dead.

Happy to post a picture, if someone can tell me how to upload it to the forum.

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

Update. I plugged in both the HDMI port and the USB port to my MacAir. I then checked the 5v and 3.3v test points. Both were nominal, within .1v of what I expected. Given that and the fact that the LEDs look OK, I now think the problem is with the display.

Does anyone know how I can do some testing on the display to confirm it is the issue? I am getting nothing on the display at this point, it has worked in the past.

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Franklin97355
 
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Re: TFP401 not working

Post by Franklin97355 »

Happy to post a picture, if someone can tell me how to upload it to the forum.
The picture needs to be less than 1meg (800x600 works) and below the reply window is a choosefile button that will let you select the file to upload.

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

Picture of active decoder board
Picture of active decoder board
IMG_0906.jpg (124.71 KiB) Viewed 414 times
OK this is a picture of the decoder board. Nothing much to see, the power and HDMI LEDs are lighted. The touch LED is blinking red. This is all normal.

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adafruit2
 
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Re: TFP401 not working

Post by adafruit2 »

hiya, can you tell us what exact display you have connected? do you know where the smoke came from? we want to avoid having it happen again and also help you determine if the display is bad or the backlight driver :)

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

It is your 7" TFT display with touchscreen, 800x400 resolution, product id 2354. I bought the driver and display as separate part #'s. The smoke came from the flexible circuit on the display.

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adafruit2
 
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Re: TFP401 not working

Post by adafruit2 »

oh thats not good! by chance did you change the backlight control?

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

Nope, I read up about it, but not not modified anything at all, other than some code on my Raspberry Pi to accommodate the 800x400 resolution.

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adafruit2
 
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Re: TFP401 not working

Post by adafruit2 »

k lets try getting you another 7" screen - email support@adafruit and ask for that. we'll see how that goes!

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Chuck0071
 
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Re: TFP401 not working

Post by Chuck0071 »

super, thanks for the help.

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