Ethernet shield with external power - only 4.2 V at 5 V pin


I have a Stalker V1 and a Ethernet shield from Seeed. When I power all from USB everything its ok, but if I use an external power supply with 9 V I get only 4.2 V on the 5 V pin on the ethernet shield. That’s really strange for me. Also I recognized that the RTC does not work under these condition. :frowning:

Any idea what is here the problem?

Best regards,

Sorry for the inconvenience brought. We will have a test and get back to you.

The JST power on the Stalker supports lithium battery but not the DC Adapter. Did you used the external power through the JST power connector?

Does your 9V adaptor can supply more than 500mA?

Yes I do so. Because I though this is the right way. Where a should I correctly connect the power to power also the Ethernet Shield?

Try short the D6(JST side) diode, and test with the ethernet shield.

I tested the same with an Arduino UNO and got the same problem with only 4.2 V on the 5 V pin.
So maybe it is a problem with my Ethernet shield?