[Elecraft] K3 does not transmit (FSK) on lower bands?

[Axel Kaiser]

I am having problems with my K3 in transmitting RTTY on the lower bands (160m -30m).

I am using MMTTY togetner with a microham microkeyerII. On the higher bands (20m-10m) RTTY works fine with the mode setting on Data and having selected FSK. But when I switch to the lower bands, the transmit LED will light, however there is no FSK shifting, no tones are being sent and no tones can be heard in the monitor either.  Transmitting voice on the lower bands is working fine though! 

I checked the menu for any band dependencies but couldn't find any that would apply to FSK transmission. Does anyone have an idea what I am doing wrong?

Axel, DL3ZH