When I turn TV on it is always on atv and not dtv how do I set it to stay on dtv

That depends upon which source your "normal" TV is connected. If you have a cable box using a coax cable, then you will either select the DTV source if the cable box uses digital output or a digital over-the-air antenna, and ATV source if the box is using analog signals or if you are using an analog over-the-airwaves antenna. If you are using a cable box but have an HDMI cable connecting it to the set, then you need to choose HDMI1 or 2 as appropriate. If you have a box that uses the red-black-yellow RCA cables, then select the AV input. Remember that for ATV and DTV inputs from a cable box, you usually have to tune the set to either channel 3 or 4 and use the box to change the channels.

Got to know the model number of your tv. If the set is only atv then you would need a decoder box to convert digital signal from antenna or cable company to analog channel or to composite input on the tv.

When you set up the tuner select analog + DTV and then do a channel search.

Need more details. Is it an hdmi hookup or a coaxial? Is your cable line hooked up directly to the TV or are you using a modem? Is it a smart TV or just regular?

No solution sorry but i have a problem too... I usually watch my tv on "dtv" now it just went black no channel is working it automatically went to "ATV" where the channels are fuzzy and my extra channels aren't working. I tried scanning on "DTV" for all the channels but automatically scanned and defaulted back to "ATV". Does anyone know how to fix this?

Have you been into scanning settings and set to DTV , it seems like you are either on ATV or have a bad Antenna connection. If signal is weak from your Antenna you can add a booster in the section between your wall socket and the TV. You cannot use Satellite dish connections to receive either ATV or DTV signals without a set top box ...

Not an expert on this model but generally if you switch the TV on by pressing the remote's power button it will come back using the input you previously used. If you press a channel button it will come back to DTV.

samsung advised  atv/dtv selection by that button not available on australian series 6