Dim display problem on large LED digital clock
The digits at one end of a large LED clock displayed much more dimly than they ought. I’d say they were about half the brightness – and it was quite a puzzle. The clock was powered by a 5v USB charger and a cable with 5mm barrel plug.
The solution appeared as I was dismantling the device to a) to disable the LDR which caused the display to dim in dark conditions and b) to look for a way to feed the LEDs with power from both ends. Having looked inside, my knowledge was inadequate.
The actual solution was to notice that the input was marked 6v and I was powering it with the supplied 5v USB charger. I rummaged through my (huge) collection of power bricks, soldered the wires to the correct barrel plug and all was well.