LoopA - Flickering Sys-Menue

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Short sayed, the Backgroundet Text is flickering, but only in Sys-Menue:

here a feedback, from Fabrice, - i built a LoopA for him:

the LCD thick selection line is grey and flickering in the “Setup” menu.
But all is OK in all other pages/menus.
And this was not the case in previous device where the selected line was a pure non flickering white thick bar.
So obvioulsy either an assembly difference or faulse contact somewhere or LCD frequency quality difference.
Now I have to learn all its features and give a feedback to the community and midiphy 😉

can you please make a short video with this flackering line - so its easyer to describe the problem

Nothing is visible on a video for this kind of things
Even that is hard on a still picure
but 5 pictures attached:

When the white inverted line is OK, it is VERY white, clean and stable =perfect. This is true on 2 of the pictures I have attached (and is in fact even more white than the 2 pictures. It’s a camera effect). See names of jpg to see these ones.

When the line is not OK, it is all grey+additionnal two even more grey strips + a bit of flickering. This is in reality more grey and darker than what is visible on the 3 pictures attached (=camera effect).

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Can sometimes be related to the power supply in use. The OLED certainly draws a bit of power, especially when a lot of white pixels are displayed. Try another PSU and/or USB cable?

You can try to add a bypass capacitor (10uF?) across the 3v3 rail of the OLED.

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I did it (both cables & power supplies) … is the same
But as you can see on the images above, some case are perfect -with a lot of white pixels- , while some not.
As Mike as copied: the difference in reality is much more visible than what is on the pictures, but as this is only in the “SETUP” menu, I think we should close this case if no other user encounters also. I would guess some HW problem (bad or wrong component, assembly, kind of hard to find resonnance ….)
Fabrice

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I haven’t heard reports of similar behaviour, but maybe it’s not too noticeable in the setup menu? Another possibility is that a BuyDisplay-brand display is used rather than the Newhaven OLED. Both work, but maybe the Newhaven is “better”. I think we’re including the Newhaven display with recent kits as Mouser won’t ship them to single parties any longer for some reason.

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its the display from the midiphy kit (buyed a few weeks ago) @Fab: is this also noticable on the Screensaver-clouds? (where a lot of pixel are activated)

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It’s ultimately a power issue caused by high-contrast regions on the OLED (horizontal bar in the setup screen) and is caused by the PSU not being able to provide enough current for short current bursts.

This can be eliminated with two options:
a) use a high quality USB PSU or powerbank (i.e. try for example an Anker powerbank with 10-20Ah)
b) implement latigid on’s suggestion and add a small capacitor of 10uF+ to the OLED power supply pins.

Note that such a capacitor is not specified in the Newhaven OLED datasheet, so they usually expect people to go for route a).

Also, other than slight OLED banding in the setup screen no other functionality is compromised, so you could also leave it as it is.

I’ve got a few PSUs (and USB cables) which show this problem. And i’ve got more higher-quality PSUs and cables which don’t have this problem. No problem also directly from a new Mac mini USB port btw.

Best regards,
Peter

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12A industrial PSU. Not in the cloud. As also said already, I do live with that without problem. Topic closed.

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I noticed the same issue with the SYS-menue. Disappears when I am using another power supply.

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Yes, this is almost always a PSU issue - the reason it happens in the configuration screen is, that there is a high contrast region (the white horizontal configuration line) - this requires a lot of “sudden current” from the PSU - if it can’t provide that, the dimmed or flickering menu bar can be seen.

All in all, this is not problematic for the proper operation of the LoopA, but two solutions exist:
a) Solving the problem at the root would be to exchange the PSU
b) If that is not easily possible, adding a 100uF to 470uF cap across the OLED power supply pins will most likely help.

Note that this capacitor (solution b)) is not listed in the Newhaven datasheets, so they would also expect a proper power supply from solution a) - i’m just pointing out an alternative, arguably a sub-par solution, but it works most of the time.

Best regards,
Peter