I plugged the 9v DC directly into the dodgy arduino and it didn't power at all but the other arduino plugged in parallel did.
Also when it is by itself the power light is VERY dim but when I plug the shield that I am using with it (its a datalogger shield) the light turns off completely.
About a week ago I was testing a different DC in, a 2amp one, and it was faulty and blew up one of the arduinos (Quite literally, it was very dramatic) Could the second one have been slightly damaged and limped along for a couple of days before it broke?
when I placed the probes on the center and right pin it read 2.03 volts, not a good sign I'm presuming!
So if I blew both voltage regulators can I assume it was the faulty DC in I was using and that the way I'm going about powering the arduinos in parallel into their Vin ports is safe if I swap out the second faulty board?
The output of the DC in is settled around 13.25V. Is that ok when its not under load?
As far as current draw the 3 arduinos I use have different draws, 2 have datalogging shields on them and draw maybe 100mA (At a Max) and the 3 is powering 3 servo's on a shield I built, they're low power, the most I've measured that arduino drawing is 860mA.