That looks like an OLED display. I don't see any indication that it would work with a 5V processor, though. Most are 3.3V only, and require voltage regulators/level shifters to work with 5V processors.
If you happen to get a dud, what are your return or support options?
I have bought this OLED and connected straight with 5V point of UNO; it has worked.
@jremington the 5V connection was mentioned by the seller here: (wiring diagram)
and also here:
I will look into that.
@GolamMostafa The Serial Monitor does not write any message even though it should based on the code. Not at any of the 3 setups. I wire the displays as I mentioned in post #17 and upload the code. It complies and uploads successfully, but no message on the Serial Monitor (nor on the displays)
You may investigate why things are not working -- change UNO or change LCD or change both or change PC; the problem is to be detected.
That's a solid idea, I had that days ago, but wanted so much to avoid sourcing an other UNO 
well I guess I will have to
If the Uno works for other uses, it is almost certainly not the problem. To test it, you can get a working OLED from Adafruit, with product support and a money back guarantee.
Hi,
No joke, I2C bus requires a 4K7 resistor from SDA to 5V and a 4K7 from SCL to 5V.
These resistors are needed to pull_up the lines.
No joke.. Read how the I2C bus works.
https://learn.sparkfun.com/tutorials/i2c/i2c-at-the-hardware-level
Tom.. 
Okay, so I see the need for the pull-up resistors. I know that they are only pre installed in Ardurino Mega, so I assume I either need to place the resistors between the A5 and A4 pins of UNO and the SCL and SDA pins of the I2C on a solderless board or they are pre installed on the dispaly's I2C board itself.
In the second case.. can you tell by the picture I posted if that is the case?
However now I am looking at the pictures posted in the review section of the item's AliExpress page, and they are just directly connected to the UNOs or Nanos pins... and working out of the box
Do you have a good magnifying glass? Look at the back of the board, at the end of the cable from the display that is labeled "30". Looks from your pictures like there might not be a good solder connection there.
So I bought a new Uno, and guess what nothing changed.
I think it should, because any guide and video online simply connects the 4 wires, downloads the liquid cristal library, an example code, and it works for them just like that.
Hi @TomGeorge ,
No unfortunately, I don't.
The schematic of the controller is given in Fig-1 which indicates that there are pull-up resistors on the I2C Bus.
I am so out of ideas.
At this point I will just give up on I2C and will try to make it work with the 11 wire method..
And give up on oled for now. I just have no other ideas.
Get yourself an inexpensive DMM?
Tom..
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