Waveshare Screen Problem

Discussion about this major DATV Project. See also https://wiki.batc.org.uk/The_Portsdown_Transmitter
G0DDX
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Joined: Tue Oct 10, 2017 8:38 am

Waveshare Screen Problem

Post by G0DDX » Thu Jul 02, 2020 3:23 pm

I had completed my Portsdown last year and it was all working and working well. It was put on the shelf, and when fired up a couple of days ago the 3.5" screen is lit up but blank and dark, but the backlight is still on..
I have tried it with a 7" screen and all works well. So I assumed it was the 3.5" Waveshare screen.
So, I ordered another one from Pi Hut (ie no dodgy Fleabay type supplier etc). It came today, and is exactly the same, and the same on 3 different Rpi's, and with two different versions of the Portsdown software.

So, I am a little perplexed as to what the problem can be.

Anyone got any suggestions other than using my 7" screen. I have the old hardware ie modulator board and 4 way switch etc, all this is built into a box that would not easily take a 7" screen. Whats more having bought another 3.5" screen I am loathed to move away from it in that box.

So does anyone have any good ideas? I'm not very computer literate so could someone point me at a downloadable image of something that I could test my screens with, namely just the 3.5" ones.

Answers on a postcard etc etc...

Thanks in advance

Geoff
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De Geoff
G0DDX

g0mjw
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Re: Waveshare Screen Problem

Post by g0mjw » Thu Jul 02, 2020 4:02 pm

Are you sure the software is running? Can you connect to it via SSH ? Scrub that - just realised it works with the 7". Maybe you need to SSH into it to configure the screen via the menu?

G0DDX
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Re: Waveshare Screen Problem

Post by G0DDX » Thu Jul 02, 2020 7:49 pm

Thanks for that suggestion, yes I can SSh into it, and can change the screen selection, but makes no difference.
I cobbled a 7" screen on it today, and managed to check the amp I wanted to test, and it worked fine on the 7" screen.

Just does not seem to like 3.5 screen (either of them and on several different Rpi's)

Geoff
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G8GKQ
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Re: Waveshare Screen Problem

Post by G8GKQ » Thu Jul 02, 2020 10:06 pm

Geoff

Please confirm what type of screen you are referring to? What does the print say on the back of the PCB?

Dave

G0DDX
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Re: Waveshare Screen Problem

Post by G0DDX » Thu Jul 02, 2020 10:36 pm

Got it from Pi Hut, usually a reputable source.
I've just run out of ideas!

Both screens are same Revision number (4.0) and original one bought 18+ months ago, new one bought yesterday

20200702_233149.jpg
20200702_233149.jpg (1.94 MiB) Viewed 368 times
De Geoff
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g4hiz
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Re: Waveshare Screen Problem

Post by g4hiz » Fri Jul 03, 2020 5:11 am

Just a thought. Have you selected 'Type A' for screen type in the console menu?

Jen

G0DDX
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Re: Waveshare Screen Problem

Post by G0DDX » Fri Jul 03, 2020 5:55 am

Yes the 3.5 option was selected, by using ssh into the Portsdown menu system.

There is the possibility that the new screen is faulty too. But i find that a little unlikely.

Can anyone suggest a ready made image of anything that uses the 3.5 screen that I coukd test them with. Obviously the Portsdown, but have tried that on two screens with 4 different Pi's to no avail.

Thanks for suggestions so far.

Geoff
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De Geoff
G0DDX

g4hiz
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Re: Waveshare Screen Problem

Post by g4hiz » Fri Jul 03, 2020 6:44 am

Hi Geoff,

not wishing to labour the point, but there is an option for a 'Type A' and a 'Type B' 3.5" screen. I have used both types on different Portsdowns and from memory, I don't think having the wrong type selected worked.

Jen

g0mjw
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Joined: Sat Sep 20, 2014 9:15 am

Re: Waveshare Screen Problem

Post by g0mjw » Fri Jul 03, 2020 8:08 am

Note what Jen said - you must select the right type. These screens are easily terminated by not plugging then in correctly but if it's new it ought to be OK. Are you using the latest version of Buster? Maybe something changed but first, I would take note of what Jen said.

Mike

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Re: Waveshare Screen Problem

Post by G8GKQ » Fri Jul 03, 2020 9:31 am

Hi Geoff

Some diagnostics for you to try using the Portsdown.

With your faulty screen fitted, and the RPi connected to your network, boot up your Portsdown. Then log in to the RPi by ssh. You should get the Portsdown console Menu.
  • Select Shudown
  • Then select "Exit to Linux"
  • at the prompt type gui and press enter
You should see some text scroll past. A screen with working touch will generate this output towards the top of the scrolling text.

Code: Select all

Supported events:
  Event type 0 (Sync)
  Event type 1 (Key)
    Event code 113 (Mute)
    Event code 114 (VolumeDown)
    Event code 115 (VolumeUp)
    Event code 163 (NextSong)
    Event code 164 (PlayPause)
    Event code 165 (PreviousSong)
    Event code 169 (Phone)
  Event type 4 (Misc)
    Event code 4 (ScanCode)
Input device name: "ADS7846 Touchscreen"
Supported events:
  Event type 0 (Sync)
  Event type 1 (Key)
    Event code 330 (Touch)
  Event type 3 (Absolute)
    Event code 0 (X)
     Value      0
     Min        0
     Max     4095
    Event code 1 (Y)
     Value      0
     Min        0
     Max     4095
    Event code 24 (Pressure)
     Value      0
     Min        0
     Max      255
Let me know what you get. Do you get any more text scrolling past when you touch the screen?

To shutdown safely, just press ctrl-c and "sudo shutdown now"

Final thought: Have you tried any of the programs here: https://www.waveshare.com/wiki/3.5inch_RPi_LCD_(A)

Dave

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