Repair.IT – Samsung Tab S2 9.7″ SM-T813

Sometimes I get an easy one. Last Sunday, I had visited my sister on my way home from badminton. She lives nearby and had helped stitch a curtain for us and we were picking it up. Anway, later that day, my brother messaged me that he had dropped off a tablet at my sister’s. I replied saying that I would pick it up the next day.

As it turned out, I was a bit busy that day so didn’t make it. Then the next few days were also busy – as I had started a part time Tafe course. Certificate IV in Cyber Security – it runs three nights a week and I found that there is also assessments that need to be done and research and other study on our own time. I had already done some other previous Cyber Security certifications, but wanted to do this Cert IV as a refresher course and to help reinforce the knowledge gained from the previous courses.

Yesterday, my brother messaged me about the tablet – which I had completely forgotten about, must be due to old age. I said I would pick it up on Sunday, which was today, and so, after badminton, I popped over to my sister’s place and she gave me two tablets. One was from my brother – a Samsung Tab S2 and the other was from my second sister, something about a battery life problem.

My brother mentioned that he had replaced the battery and that afterwards, it just wouldn’t power on. I got the tablet out of its case, and noticed that the back wasn’t sitting properly – so after sliding my fingernail around the edges – the back was loose and could be removed.

I verified that it would charge, by connecting a micro USB cable to it and sure enough, after a moment, the display showed the battery capacity around 98%.

I disconnected the cable, then did a visual inspection. I noticed a connector on the side which had dimples on it – where contacts would fit, but could see no contacts on the back that had been removed. Continuing on, I checked that the battery connector was in place – which it should be since it was able to charge.

Pressing the power button caused no reaction from the tablet, then after further inspection noticed that the five contacts on the connector seemed to match with five contacts on the main board. Apparently this connector is meant to be flipped over and sit on top of the other five contacts. Retrospective review of the back also showed that the connector sits in a little frame and is held down when the back is put back on.

This connector is meant to be flipped down and sit on those five contacts on the edge of the board.

I flipped the connector over, so that it sat on the contacts, pressed the power button, and sure enough – the tablet powered on. It looks that the design is such that if the back cover is removed – it prevents the tablet from being turned on – sort of like a fail safe to prevent damage when poking around inside the tablet. The back of the connector has some sticky surface, which might be why it stuck to the side of the case.

Anyway, it was a relatively easy matter of aligning the back cover with the small molded frame and then press all around to clip the back cover back into place. After doing this, I put the tablet back into its case, then pressed the power button – Voila!, it turns on. Fortunately the cable on that connector had not been damaged by being bent over like that.

So this was an easy job – I wish they were all like this. Another successful Repair.IT. Next is to see about the other tablet.

Rotate.IT – Raspberry Pi 3 with 7″ Touchscreen display and new OS

This is an update to a previous article https://j0hn88.wordpress.com/2017/04/08/remake-it-raspberry-pi-3-with-7-touch-screen-and-housing/ where I had to modify the housing to prevent pressure on the touchscreen cable. I had a project for this Raspberry Pi, so got it out and when I powered up, I found that touch didn’t seem to be working. The display was coming up in a text mode – somehow the graphical desktop wasn’t running.

I removed the back housing and noted that the touchscreen cable was slightly bent, so decided to modify the case by filing the edges wider than I had previously done. I rounded the edges a bit more as well, so that should fix the problem. Next was to find out why the graphical desktop wasn’t running.

After checking the Raspberry Pi website, I noted that there had been a lot of updates. This was normal since the last OS I installed was in April 2017. The website suggests to download and then run the Raspberry Pi Imager, which will then allow me to choose the operating system.

I did this and chose the Raspberry Pi OS (other), then which is a port of Debian Bullseye with the Raspberry Pi Desktop – Released 4th April 2022.

After the writing to my micro SDCard was finished, I put that into the Raspberry Pi 3. Power up and then noted that the display was upside down. Ok, I know how to fix that – so continued with the configuration. Finally the configuration was completed, which included a large update that took some time, especially since the Pi 3 was connected via wireless.

I made the change to the config.txt as follows:

sudo nano /boot/config.txt

add a line that says lcd_rotate=2

save the file, exit and reboot. This time, the display comes up the right way up, and then the desktop showed up – upside down. What gives? I check with a Google search and it seems that a lot of people have had this problem, and the only fix I found was that someone had installed a previous release based on Debian Buster.

I got out another 8GB microSD and downloaded the older release from 7th July 2021. After the microSD was written with this image, I put that into the Pi 3 – and went through the same configuration, except this time – I only needed to make the same change, and ended up with a desktop the right side up – fantastic. I then considered that it was a bug, but if it was a bug in the Debian Bullseye port to the Raspberry Pi, then it would have been fixed, or would it?

Ok, if it wasn’t a bug, maybe I am missing something. I put the updated microSD back into the Pi 3 and started looking into the problem. I found a note somewhere that suggested that lcd_rotate was deprecated – which doesn’t sound right, since it obviously did something. I found another that suggested using display_lcd_rotate=2. I tried this and that didn’t fix it

The status currently is that without lcd_rotate=2, when the Pi 3 was powered up, the display would be upside down. With lcd_rotate=2, then on power up, the display is the right side up – but then after a short time, the display blanks – maybe when it is setting up the graphical desktop, and comes back upside down.

I left this as I had to do some other work, but got back to it today. After another fruitless search of Google, I wondered whether we were all missing something – was there a new configuration parameter? Eventually, I ended up at the documentation https://www.raspberrypi.com/documentation/computers/configuration.html

Within this documentation, then went to Rotating your Display. A Eureka moment occurred! Lightbulb flash! The OS I downloaded did include a desktop (which is the graphical environment). I needed to use the Screen Confguration Utility to make this change.

The Screen Configuration Utility wasn’t found under Desktop Preferences, but can be found from the Applications menu, Preferences, then Screen Configuration.

The above is from the Screen Configuration Utility, click on Configure, Screen, DESI-1, Orientation, inverted. Then click on the green tick to apply it. Then within 10 seconds, click the OK button to keep the changed.

So if you see the DSI-1 shown upside down – then that is what you want. What gave me the idea was that the documentation noted that xrandr can also be used to make the changes. xrandr shows this:

The desktop graphical environment is inverted to get the display the right way round from my case and housing – so this is the fix that I needed. When in doubt, RTFM as they say. Now, this isn’t a complete fix but is a good workaround, and allows me to use the most updated operating system with the Raspberry Pi 3. If I reboot, using the sudo shutdown -r -t 0 now command, there will be periods of upside down display output, but eventually I will end up with the desktop environment showing the right way up.

It appears then on power-up, that the lcd_rotate=2 will apply during the initial bootup, then the screen blanks and the default configuration takes over which shows an upside down display, then the desktop will come up afterwards, the right way up. This will happen with the Debian Bullseye port to the Raspberry Pi OS. Using the Debian Buster port of linux – lcd_rotate=2 is all that is needed.

Anway, I was able to Rotate.IT – get the display running the right way up for my Raspberry Pi 3 with the official 7″ touch screen display.