2.7" 128x64 OLED Graphic Display Module Kit - garbled screen

Hi Core,

I’ve posted this topic at the Adafruit forum, but am posting it here also as I may have a defect display module, which was delivered from core electronics today.

I’ve soldered the header and jumpers as described on the Adafruit website, but am getting a garbled display:

I’ve tested the header connections with a multimeter and they seem okay. The voltage across pins 1 and 2 on the module is 3.12v (i.e. not 3.3v). It’s hard to test the integrity of the jumper resistors on the back of the display (R19 and R21) but they seem okay.

Do you have any idea what the cause is? An internet search suggested others with similar problems ending up finding that it was either a defective display module, or HC4050 level shifter.



Thanks for your message. It’s hard to say as there are 5 moving parts:

  • Uno
  • Wires
  • Breadboard
  • Level Shifter
  • OLED Display

It’s not likely going to be the OLED, as they are electrically tested post-manufacturing. It might be best to test with a 5V-native Arduino of sorts, to remove a bunch of the uncertainty. Doing a quick continuity test between each connected pin would be good as well.

Hi Graham,

Thank you for replying.

I did have an old Uno, which I connected up and got the same result, and moved the connections around on the breadboard, which didn’t fix the screen issue.

A continuity test between each pin and the jumpers passed as well. I feel I’m stuck now.

I agree it seems unlikely that an OLED would fail to produce a garbled screen like that. Given that the voltage was low could it be the level shifter?


Hey Kenneth,

It appears that the Arduino and the display aren’t causing the issues as generally when items such as these have faults they fail to operate completely. If you have another IC of the level shifter to test the system against on a new breadboard (if possible) and check all the soldering on the boards to ensure that there’s no shorting (easily not recognized in a continuity test) we should be able to further verify that the board is in fact the faulty part. All the best with it!

Core Electronics | Support

Thank you for your reply,

I don’t have another level shifter - could you send one out?

Hey Kenneth,

We’ll see what we can do to help. If you can shoot an email through to support@coreelectronics.com.au I’ll check our stock and see whether there’s anything else we can do personally to support you with your project!

All the best!

Core Electronics | Support