help for a possibly faulty LCD display

[i2NDT]

I switched on my pi with the LCD display misplaced on the GPIO socket...
now the LCD (in the correct position) lits but nothing else appears on the screen.

the pi works and I can log in via SSH and play with the OS.

my problem is: how can I determine which is faulty? the pi's GPIO or the screen???

i2NDT Claudio

[G8GKQ]

Hi Claudio

Sorry to hear that. I have done the same thing once but must have been lucky as my screen and RPi survived.

Which way was it displaced? We need to work out which pin might have gone where. The main problem is the 5v on the GPIO when most pins will only tolerate 3.3v.

Dave

[i2NDT]

thanks Dave!
the LCD was shifted 1 pin...so pin 1 GPIO was connected to pin 2 LCD bord!
I attach e picture: it's not the best, but my camera cannot take macro.

DSCN0434.JPG (816.31 KiB) Viewed 7419 times

[G4HTZ]

Hi Claudio
I done the same with my 1st waveshare screen ..but pin the otherway to yours ...mine still displayed ok but touch function had stopped working .

2nd screen I got displayed ok ..but touch never worked from the start so returned it to Amazon for a refund ...waveshare said they will send me a free screen ...still waiting.

I have now upgraded..to a 7" screen from element 14 which works ok ...plus you don't need a stylus .....obviously this may not be continued to be supported in the future .

Steve G4HTZ

[G8GKQ]

Hi Claudio

I have looked at what pins were connected to what, and quite honestly, anything could have happened.

You could write a short program to toggle all the GPIO pins to test them, and check the supply voltages on the GPIO Connector - If that works OK, it is most likely to be your display that is faulty. Or you could borrow an RPi from someone else to try (an RPi2 would do).

You can find the Pin function listing here:https://wiki.batc.tv/PTT_and_band_switc ... onnections

Otherwise, I think that you need to replace both.

73

Dave

[i2NDT]

thanks Steve and Dave for your replays!
I checked the voltages on the GPIO socket and they are OK.
I am not able to write the script you suggested Dave.
I have a RPi 1b: do you think I can use it to check the LCD?
otherwise I will buy a new LCD and try my luck!

Claudio

[G8GKQ]

Hi Claudio

I do not know whether an RPi 1b will work, so it would not be a good test.

I suggest that you order a new LCD.

Dave

[i2NDT]

I will do it next week!

Claudio

[biker_bob]

If you have a Rpi1 you might as well try it.
If the screen works then it's OK, if it fails to function then it proves nothing.
If it costs nothing to give it a go and it 'might' save the cost of a screen it's probably worth a go.

All that said, it's been a week so I might be too late.

[i2NDT]

just to close the post...I bought a new LCD which arrived today and...it works perfectly well!
so the Rpi didn't suffer at all I hope as I still have to test the outputs to the modulator and accessories.

the old Rpi I had (I think ver. B) was not suitable as the signals needed for the LCD were assigned to differet pins.


best 73
de
i2NDT Claudio