How can I use external J-Link on pca10028??

[J.Kwon]

These pins do not work when I connect to nRF51822 module directly..

Like this. I cennceted VDD, SWDIO, SWDCLK and GND to nRF51822 module.

And there are not jumpers to discennect nRF51422 on board..

[FormerMember]

No, the SDK examples should work on any board. Just be aware that the default setting for the LFCLK in the SDK examples is "external 32 kHz crystal". If your board doesn't have an external 32 kHz crystal, the LFCLK source should be set to the internal RC oscillator.

[J.Kwon]

Thank you. I seccessed by changing the clock source to RC oscillator.