Raspberry Pi 5 Volt 3 Amp Adapter Repaired
Like all those Raspberry Pi users that use the newer 3B and 3B+ Pi’s that consume more Amps I used an 3 Amp 5V adapter to be safe.
And I added a new Adafruit PiTFT 3.5 inch 480×320 touch screen to make it more portable. Those need about an extra 120 mA current for the backlight. Which still would be within current limits for my 5V 3A Raspberry Pi adapter to work.
But suddenly after quite a few Raspi re-boots the hardly used brand new adapter no longer provided the needed 5V power. Which was completely unexpected.
Opening the plastic case was very easy and just with a screwdriver I could open the clipped case.
And I was almost sure nothing really bad could have been causing this. And as I thought it was just the primary Inrush current limiter resistor used as fuse that had gone bad. (see red arrow marking).
Above the bad resistor that was replaced. After a new resistor was soldered in its place my 3A adapter was working and my Raspberry Pi fully operational again. As next photos show:
Just my 3.5 inch new PiTFT 480×320 touchscreen did not yet work because apparently they only are easily installed when an active online connection is used. Because I in vain tried for a long day to get the Pi TFT screen operational and for the time I decided to give up trying to get it working.
On some sites they claim that it can be done offline too, but I do not think that I can if I do not have the right matching driver for my new TFT touch screen. And because it is python (3?) and maybe some Linux code I think it is far from easy! And most sites share a lot of useless crap! While even their Raspi installer and their images do not install and so do not work at all! It is a real shame that they sell these new TFT screens without any given appropriate screen drivers! It is still firmware that rules in these modern electronic days!
Above my again to my Raspberry Pi connected working HDMi monitor after the cheap China Aliexpress adapter was fixed.
It looks however that it still will take some time before also my new 3.5 inch TFT screen finally works. Although they said in the advert that it was just a matter of pluging it in on my Pi, it sadly was just a false promise to sell these touch screens. Which only would be true if the missing driver wasn’t needed and the hardware already contained this configuration in an eeprom or some equivalent chip on board of this touch screen.
A day later I finally found the reason why this brand new bought PiTFT plus 3.5 inch touch screen refused to work. And why only the white backlight from this on the Elektor website bought resistive touch screen worked. Apparently it was sold as a new screen for Pi Zero, Pi 3, Pi 2 and models A or B. But my Raspberry 3B+ never worked with this display, and it neither was just easy plug ‘n’ play as was mentioned on their website, and it neither was equipped with an extra hdmi port for another display as was promised. Only when I installed this probably already 4 years old dated PiTFT screen on an older Raspberry Pi 2B+ model it finally worked on a specific for the Raspberry model Pi2B+ designed PiTFT image.
In my humble opinion any new device that needs an online connection just to get it installed is something I should’t trust or even should buy! This sadly also shows that all good things also come with a catch. Because now that the internet is part of our daily lives everything these days only seems to work online connected. Which in my opinion is something that is nothing more than a dangerous development. If in future not only our personal data can be found online, but also the temperature of our homes, the content of our refrigerators, the webcam in our laptop, or the temperature of the water in our showers can be managed and controlled from the outside by any unfriendly hacker. And the problem in all those cases already becomes major if someone just causes a power line shortage.
Until another probably also unexpected repair!
Albert van Bemmelen, Weert, The Netherlands.
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Note: You can read his previous repair article in the below link: https://jestineyong.com/pickit3-programmer-repair-after-mplab-deadflashed-it/
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Andrew F. Ali
December 16, 2020 at 10:24 pm
Very innovative and informative. I agree with you totally.
Albert van Bemmelen
December 17, 2020 at 12:00 am
Thanks Andrew. A datasheet for the PWM LY2223 controller in this Raspi adapter strangely couldn’t be found anywhere but it looks similar to chips DK106 and DK124. (pins 1 to 4 of the LY2223 are all connected as mosfet output). And although the power adapterboard also was equipped with a very bright green Led on the secundary side, it wasn’t visible on the outside of the black case of this adapter! Apparently these 5V 2,5A adapter boards completely assembled without case cost just about 50 dollar cent a piece or even less! However shipping costs are much higher, and probably just replacing the resistor like was done in this repair is still cheaper and much quicker.
Albert van Bemmelen
December 19, 2020 at 7:16 pm
In case sommeone is searching for those just 50 eurocent costing boards, here is the link
Paris Azis
December 16, 2020 at 11:34 pm
Albert, apart from the technical presentation of the present article,which is very nice as always, I fully agree with your epilogue sayings...
Albert van Bemmelen
December 17, 2020 at 1:57 pm
Nice to hear from you Paris! As you know too many things already happen these days we can't control. Things that humanity wasn't prepared for in any way. Why it sure would be nice if we at least can control installing our devices successfully without the complex online scripts or structures they put us up with. That only work in the end after a long wasted trial and error method. God knows how many Raspberry images on both my Raspberry versions I already had installed before one finally worked! (And just installing those Raspberry Pi images one after the other on several SD cards takes a lot of time already anyway!)
Pe Than Htun
December 17, 2020 at 2:42 am
The same for me regarding Pi touch screen. I bought tft screen from on line store and never successful installing driver for my pi 3b. One thing though I didn't have 3 Amp adapter and instead used 2 Amp phone charger.
Albert van Bemmelen
December 17, 2020 at 1:35 pm
Maybe you just have to find the for your TFT screen matching chip driver with a correct Raspberry image like I did? And maybe try it also on an older version Pi. That was the only thing that worked with my Raspberry Pi 2B+. Although I previously also had tried without any success the Python scripts as suggested on all Pi sites. It looked as if the comments like => cd /boot, sudo tar zxvf LCD-show.tar.gz, cd LCD-show/ were successfully executed but my PiTFT plus screen never started working this way. I also was able to place the LCD-show map manually extracted on the Pi desktop but still none of the tried LCD drivers worked. I guess the MP13501 or the MP13508 just weren't the right drivers for my Adafruit STMPE610 + HX8357D 3.5 inch touch screen! I hope you now also will be able to activate your screen by finding the right driver or driver image!
Albert van Bemmelen
December 17, 2020 at 2:33 pm
Maybe the instructions on this (also complex) Adafruit link helps to investigate your Raspberry Pi screen?:
https://learn.adafruit.com/adafruit-3-5-color-320x480-tft-touchscreen-breakout?view=all
Albert van Bemmelen
January 3, 2021 at 1:17 am
In case this helps, today I was able to install a new 3.5 inch TFT 480 x 320 screen onto my Raspberry Pi 2B+ OFFLINE almost automatically. I did following: 1. downloaded the LCD-show files from https://github.com/goodtft/LCD-show.git and downloaded the newest 02 december 2020 RaspberryPi Image (the largest one).
2. copied the unpacked Pi image onto a new 16GB microSD card with Etcher. (Etcher also validates the 'burned' image after it is installed!).
3. Then placed all files from the Github LCD-show(-master) map unpacked into the root of the SD card now named 'boot'.
4. Booted my RaspberryPi2B+ with this microSD card and after its Pi OS was ready opened the command Terminal and gave following comments:
sudo ./LCD35-show (also preceded by the comment: "cd /boot" in case it doesn't see the files).
After the given comment the Pi starts installing all necessary TFT screen files automatically and the Pi resets afterwards automatically with the working 3.5 inch screen. Complete with working touchscreen! Probably with the screen desktop 180 degrees turned. But if you add "lcd-rotate=2" to the config file in the root of your Pi SD card that is easily corrected if needed. My new TFT screen was a newer 3.5 inch LCD touchscreen that had a smaller GPIO connector opposed to my previous LCD that only worked after installing it with the right image for my RaspberryPi2B+. My newer screen used the newest RaspberryPi Image and was successfully manually upgraded to work with a TFT screen. So it can be done OFFLINE! Good luck too!
Albert van Bemmelen
January 3, 2021 at 1:51 am
The newest mentioned RaspberryPi OS (https://www.raspberrypi.org/software/operating-systems/) also has a lot of interesting new (also on Electronics!) tools like an integrated SD card Copier. With which copying your new installed SD card onto a new empty SD card placed in an external USB SD card reader/writer is extremely easy and very useful!
Albert van Bemmelen
January 3, 2021 at 1:58 am
Of course where I wrote comments better read commands instead! I am glad that installing a new TFT LCD offline manually finally worked! Just re-using a new LAN connection to stream content to my PC and vice versa kept failing again because apparently as usual Windows objects in letting the connection through! Using a Pi is never easy enough just yet!
Albert van Bemmelen
January 4, 2021 at 3:02 am
Addendum: rotating the 3.5 inch goodTFT LCD screen with command lcd_rotate=2 doesn't work on these newer Alieexpress cheap touchscreens!
Neither does adding display_LCD_rotate=2 work at all! But if you already installed the right TFT driver (your TFT screen already works but only 180 turned wrong), you just execute this on your Pi, and everything is working correctly!: cd LCD-show , sudo ./rotate.sh 180. And it is automatically saved to the SD card. Copying your Pi SD card with the integrated "SD card copier" however never seems to produce correctly working/booting Pi booting copies. And even the Win32Diskimager windows PC file doesn't seem to do just that either. No idea why??
Albert van Bemmelen
January 4, 2021 at 4:30 am
Also found why copying the fine working completely installed SD card previously failed. Apparently WIN32DISKIMAGER only works copying the original SD card correctly when the .img format is chosen! So I now finished successfully installing 2 RaspberryPi TFT touchscreen Pi's. Only if we know how to do that, it is easy as pie!
Randy
December 17, 2020 at 6:25 am
yep, this always on internet nonsense has got to go, I hate that so many things will not work unless connected to the internet, where anything can happen as you noted. We need to insulate ourselves from this evil culture.
Albert van Bemmelen
December 17, 2020 at 8:33 pm
Maybe one day our lives depend on a live internet connection. Like now the 4G network is used for exact time controlled manufacturing of cars in Aachen Germany. Where robots interact with human workers simultaneously. And where every action is timed in microseconds. Let us hope that it also improves the quality of life in the near future, because for now robots still haven't taken over all heavy and dangerous jobs.
Albert van Bemmelen
December 19, 2020 at 3:53 pm
Oops it was about 5G. See https://www.rfid-wiot-search.com/e-go-mobile-the-revolution-in-automotive-production-starts-in-aachen
Parasuraman S
December 17, 2020 at 1:18 pm
Good and informative article and cautions from true experiences! Many thanks for sharing!
Albert van Bemmelen
December 17, 2020 at 2:01 pm
You know Parasuraman that I always appreciate having a nice and much valued reply from you!
Lynn Blakely
December 18, 2020 at 4:18 am
Sirs: Albert & Parasuraman S are both excellent teachers as well as repairmen. I congratulate both of You.
Albert van Bemmelen
December 18, 2020 at 1:42 pm
Your nice comment is greatly appreciated dear Lynn! There is always something to fix and write about, and new stuff to learn which I hope keeps it interesting.
Humberto
December 18, 2020 at 1:04 pm
Hi Albert. Thanks for sharing your expertises. We are opened-mind when it comes to learn more
Albert van Bemmelen
December 18, 2020 at 1:57 pm
Indeed Humberto, we as they say 'eat and drink' electronics every new day. Its our way of living in 'every breath we take' (LOL). And if something refuses to work we are eager to fix it. And if it saves us some money it is time well spend!
Yogesh Panchal
December 20, 2020 at 11:45 pm
Albert,
2 Ohm Resistor having too much responsibility...
I remember few years back i received one Chinese cheap play station for power adapter (SMPS)issue for giving only 2.7V out put on Rated 12V DC.amp rating is odd figure i did tried to repair but no success because PWN IC was burnt so i given it back to the customer as non repairable condition. some how customer managed 12V Linear power adapter with 3amp rating & still he is using that adapter in working condition since i think 6 to 7 years.as you are aware of cheap power adapter does not have any fuse protection.
Albert van Bemmelen
December 25, 2020 at 5:06 am
Apparently it was a 4.7 Ohm 5% resistor in replacement adapter boards.
Edd Whatley
December 21, 2020 at 6:42 am
I do see that the link referenced power supply that you gave us is using a 4.7 ohm surge /fuse resistor . . .while yours appears to be using a 20 ohm resistor.
Since I can't physically inspect it for a faded band.
Therefore . . . . with the other supply having a bit heftier fusing.
73's de Edd