We are ramping up production of a new board, when we notice that some units advertise on the wrong frequency!
Most boards advertise correctly on channels 37, 38 & 39 and seems to have full function
But some boards can not be detected when scanning, not even with high end bluetooth analyzer. Spectrum analyzer reveals that RF output
energy is present only at 2460Mhz and 2480Mhz, which is not correct.
We have checked/replaced the crystal.
We have also loaded Dialog Serial Port Service template project, to exclude any problems with our software
The bad boards still show the exact same advertising frequency problem
Any tips what can be the problem, or things we could try?