Matrix OLED flickers

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Hello.
Having problem with Matrix OLED.
It flickers few pixels left and right.
https://photos.app.goo.gl/gZ7ArNZaw3fpjRUQ7

Tried to add a bigger cap for display, switched PSU, tried to use linear regulator instead of switching. No luck so far.

Anything else to check or test another display?

Otherwise it’s getting together and this thing is a beast.

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What PSU are you using? We found that the regulation can make a difference, at least for the LED driving. But the power will actually be derived from the 3v3 on the Waveshare board.

I would suggest to reflow the header pins and try to clean with isopropanol or a contact cleaner. Maybe some flux residues are causing issues. You could also try to carefully reseat the MCU board (making sure to not bend all of the header pins, so lift it up straight).

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Used a 1A one before connecting other boards. Then used something from Meanwell. Have one linear PSU. Will test it.
I can also hear coil whine on OLED.

Will give a proper clean and some reflow. Also test linear PSU.

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@Adrian you can also try populating C1/C2 (marked as DNF in the BOM) on the MatriX core backside with 330nF to 1uF unpolarized SMT caps (whatever you have available) - this should help stabilize the power supply to the OLED. This is only required, if the PSU is not beefy enough or does not have enough filtering.

Best regards,
Peter