I2c address problem on 128x64 OLED

I bought a Monochrome 1.3" 128x64 OLED display very recently, and since I connected it up to a raspberry pi zero, I can’t get it it to show anything.

The i2c address of the device is 0x3d, but each python program I run, fails because it is looking for an address of 0x3c.

How do I solve this problem.

Having an i2c address of 0x3D would suggest that the address select jumper has been cut?
If thats true, soldering a jumper across the ADDR +1 pads should put it back to 0x3C, which is the default address.

This is the one I bought:

I can see at the right hand side, underneath, that it says i2c addr 0x3d, but I can’t see which are the ADDR+1 pads. Maybe 0x3D is the default addresss for the display??

Ah Ok, I thought it was this one.

On yours I would say its the A0 pads. Shorting those will change the address, I’m not sure what it changes to though as thats not listed anywhere?

Bingo!, that’s done it thanks. I admit I was a bit wary of soldering a jumper onto those AO Pads, but it works now.
One python file/code works, but another one doesn’t. I’m not getting the same connection errors now.

Just out of interest, does the one you have , have an i2c address of 0x3C

I don’t have an OLED, not yet anyway. I was mulling over adding a small display to my Pirate Radio, I was looking at something more like this one though.

Nice, but out of stock just now

I’ve already spent my Christmas budget anyway. I did buy some Breakout garden i2c boards though. A couple of RTC’s, UV sensor and light sensor board. I just soldered the headers on them this morning. I’ll plug them into a breadboard and play with them over the weekend. Make sure they are all working then put them away to play with after Christmas. To many other things on the go to do anything other than just make sure they are working at the moment.

After getting it working on 0x3C yesterday, the OLED display is now not working at all. No i2c address or anything, and all it does is return input/output error.
I’ve hadn’t a week yet

Double check your wiring for a lose connection somewhere. input/output error usually means a bad connection.
How do you have it wired up, headers soldered on, solderless breadboard with jumpers?

Wired up with breadboard jumper wires, and they were fairly tight on. It was working fine earlier, then just stopped working. Yes the 8 pin header was soldered on as well.
This what I get:
i2cdetect -y 1
-bash: /usr/sbin/i2cdetect: Input/output error

I’d undo the jumpers and reattach them, one jumper at time one end at a time.
I have one of my builds where I connect my breakout boards via female to female jumpers. Every once in a while it errors out. If I unplug my cables and reattach them its fine again. At some point I’m going to disassemble it and clean all the male headers with alcohol. It transitions from indoors to outdoors and gets some condensation some times. Its a portable weather station.

I have one of those 40 pin extension boards connected by a 40 pin ribbon cable from a breadboard to the pi zero, and I’ve dropped the oled display into the pin holes on the breadboard. I connected the display by male jumper wires to the extension board, and tried ic2detect -y 1 again. This time it went through the scanning process, but didn’t show up any address for the display, so basically, it wasn’t found.

If its not the wiring I’d say the display has failed? I don’t think its a software issue, I’m far from being any kind of expert on this stuff though.

I don’t think this is your issue but I’ll mention it just as a FYI post.
On those long solderless breadboards there is a break right in the middle of the two power rails that go down the sides. If you look at this one you’ll see the two colored stripes have a break in the middle. The first group of 25 is not connected to the second group of 25. This has caught a few people out where they were missing a ground or power connection.

Yes I know about those boards with a break in the middle, and I have already joined both halves together with black and red jumper wires on both sides. I used the same board for something else a while ago, then removed a couple of parts/devices to accommodate the oled display.
But thanks anyway.