Power through USB is fine, but power through Vin is not working

Development Tools IDE 1.x
1

as title says....

took everything out for a field test and when i hooked up my battery (12.93 volts) to the Vin, nothing happened... thought I made a mistake and fried the board somehow but everything else seems to be working fine...

Any ideas into how to figure out what went wrong???

2

When you hook up Vin and Ground to the battery do you get 5V on the 5V pin (relative to Ground)? If not, your 5V regulator is probably dead. It is not used for USB power.

3

if that is the case, would it just be a matter of un-soldering the regulator and soldering in a new one?

4

If 12.93V is getting to the input side of the regulator and you are not getting 5V out the other side then replacing the regulator is likely to fix the problem. If the 12.93V isn't getting to the regulator then you have a different problem, like a bad solder joint or burned trace.

5

I'm having a similar problem. When I connect 12V to the Vin pin or to the 2.1 mm connector the power LED lights up but nothing else seems to happen. The 5V and 3.3V pins only give out 2.5V though, so does this mean the regulator is bust?

The board still works from the USB.

Thanks

6

Sure sounds like 5V regulator is dead, or something else is dragging the 5V down. You have volage at the cathode of the reverse polarity protection diode? Is anything hot when the board is powered?

7

I've taken mine out of the circuit so there's nothing else to drag it down. Before I had a couple of potentiometers connected to 5V which were dimming the power LED, when I disconnected them the LED got brighter and something on the board started ticking. I'm fairly new to the board so I'm not entirely sure what's what.
When using the Vin pin there is voltage at the cathode, none at the annode. Nothing seems to be getting hot.

I'm testing with a 10V power supply just now, from left to right the voltages on the regulator pins are 0V, 2.5V and 10V.

If the regulator is dead, where would I get a replacement (in the UK) or what should I replace it with?

8

Part number is on the schematic, I think NCP1117ST50T3G, but check the schematic on the Products page.
UK: Newark, Farnell, RS I think are all UK suppliers.

9

Thanks for your help, I'll try and get it replaced