While I cannot find anything in reference to resistors in the manual for revision 1.23, I see in revision 3 the following: . Connect the Breadboard Cable to the Communication/Power Header on your LVK204-25 and plug the four leads into your breadboard. The red lead will require power, while the black...

Hi Tino, Any other suggestions to check? Do you have a VFD version of this board you could compare to my photos? As you can see there are no pullups on my board where they are on yours. The screen works fine over a serial port, I assume if there was a short on the i2c bus, then the screen wouldn't w...

I am still looking for shorts, but I will admit it is a little hard to check everything as the two boards can't be separated without desoldering and it appears that at least some of what I would be interested in is sandwiched in the middle. Could you check the resistance between the clock and data l...

My board seems to be populated with quite a few different components than yours.
Also, the solder pads next to the J0 - J3 jumpers on yours are bridged, mine are open.

Hi Tino, Can you confirm your jumper settings, I have J1 and J2 on which is the default. The address should be 0x5C (8 Bit) -> 0x2E (7 Bit), 19200 Baud Are you using the internal pull ups on the Arduino? It seems like whenever I have the display attached it blocks execution on the Arduino If I start...

I have tried both the internal pullups of an Arduino Uno as well as external 1k pullups on 5v and have no luck either way so I don't think it is that.

The manual doesn't specify that I can see, but is any pullup needed on the data and clock lines?
I read somewhere, maybe a newer revision manual that 1k - 10k pullup can be used, but I don't see anything of the sort for my display.

I have an old (new in box) VK204-25 VFD that is revision 1.23. I am having issues getting the VFD to do anything via i2c, everything works fine with the built in RS232 connector. I have tried every manner of getting some kind of command to work over i2c, but nothing. I cannot even see the device wit...