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General => Off Topic => Topic started by: d0ugparker on November 23, 2020, 10:53:28 PM

Title: Screen waves or ripples and static with hard drive activity and mouseover action
Post by: d0ugparker on November 23, 2020, 10:53:28 PM
I have a generic trade show kiosk with an ITX motherboard whose 47" touch screen is rotated into portrait orientation. With every disk access, it seems, and with every mouse movement from mouseover text item to mouseover text item, there almost always seems to be an equivalent, slight waviness that appears slightly in the screen, and also a bit of static on the speaker in exact relation to the waves or ripples on the screen. Not having had a trade show kiosk before, I have no idea what might be causing the visual and sound artifacts I'm getting. The speaker works well, otherwise, as does the monitor and touchscreen.

Well, I think I may have an idea, and I'm wondering if it could come from isolated PCB and component grounds—that whoever built it took the monitor's PCBs apart, reassembled them and other parts into the trade show cabinet, but maybe never grounded all the individual chassis grounds together. If so, now all the ground levels are floating and maybe causing the static.

If the individual components need a common ground bus, will that ground be different from the mains ground? I'm not an electrical engineer or electrician.

Is there anyone familiar with building and debugging trade show kiosks who can give me any pointers?