Usb DP board

will do this tonight after work,
cheers for helping us out gus.

@ ransomhall
our boards are not being under fed.
the boards work perfectly (albeit not all modules due to lack of power from usb) when only a single power source is plugged in.

its only when the two are plugged in together that this becomes an issue.

sorry it takes me so long to reply, work is very busy this time of year.

I got hold of a Multimeter today and observed:

USB direct connect to PC (works OK)

C1: 0
C2: 4.55
C3: 4.59

USB direct connect and wall wart (when problem occurs)

C1: 4.97
C2: 4.28 - 4.42 (fluctuates as the device is resetting / painting lines or screen goes white)
C3: 4.82

Power from wall wart only (works OK)

C1: 4.96
C2: 4.93
C3: 0.53

I hope this makes some sense to you Gus - I am very much a software person and don’t really know my way around hardware :-[

Also, interested to see the observations from Virus.

Interesting! I think I know the problem and we will try to repro on our end.

Thank you very much for helping.