I'm struggling with hassle-free powering a Raspberry Pi Model 3 together with the official 7" touch LCD, avoiding the yellow flash of insufficient power supply in the display during operation.
My Raspberry Pi Model 3 has two USB devices attached: an Edimax WLAN dongle, as well as a Logotech universal receiver. Yes, I need a second WLAN in addition to the built-in.
1. Attempt: original 2.5A USB power supply, connected to the LCD touch. Using a short USB cable then from the display to the Raspberry Pi 3. The result: especially during boot the yellow flash is showing most of the time.
I've tried several different USB cables between the LCD and Raspberry Pi, but to no avail. Again, the yellow flash is with too many a time.
2. Attempt: 5A USB supply, with 2 short USB cables wiring up LCD and Raspberry Pi separately. This works quite satisfactorily. Unless I hotplug USB devices, but that sems to be a well known problem, so a powered hub is thr cure. However, the cabling is cumbersome, as the only reliable way I've found so far is using very short USB cables, around 10cm each.
So, is it even possible to wire the power supply in sequence, first the LCD, then the Raspberry Pi? What cables do I need and where can I get "heavy gauge" USB cables that actually work in this scenario?
Or is this the wrong wiring anyway? Reading through the official documents seem to suggest that this should work. Anyway, where can I get good USB power cables, as these seem to be the really crucial component here...?