I have a Samsung smart tv. We use a harmony remote to control it. We are unable to shut it off, adjust volume, change stations

unless you have a volume modulated type set, the volume is set by the transmitting station. It is quite common between channels and distance from the station to the set
talk with a tv tech expert in a retail shop or repair shop

Try to set the remote control with an other setup code.

When i went into the Harmony software, your TV did come up. If these codes aren't working try a different model Samsung (like UN46D6000). All new Samsungs use the same code set. If this still doesn't help, go to "Devices"->"Settings"->"Adjust Inputs"->"Method 3". Follow the directions from there. Something else that may help is Samsung calls it the "Source" button, Logitech calls it "Input x".

Is the remote set to adjust the volume on the TV? If it is going up all the way to 100% or Full on the TV then suggest checking the source. On some cable and satellite boxes they have a built-in volume control also. If that is set low, that would affect the amount of volume coming out of that device.

Please try adjusting the Power on delay before testing any other settings.

My Harmony remote sends commands too slowly when I press a button when in an Activity (Adjusting the Inter-key Delay)

http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=12706

My Activities never work correctly when first powering on my devices with my Harmony remote (Adjusting the Power On Delay)

http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=12333

My Harmony remote doesn't switch between Activities correctly without having to use the Help button (Adjusting the Inter-Device Delay)

http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=12696

My TV always stops short of the correct input when switching Activities using my Harmony remote (Adjusting the Input Delay)

http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=12707

Adding commands to be sent at the start or end of an Activity for a Harmony Remote

http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=10265

Learn the volume commands for your TV and Receivers. This will resolve your issue. Please see the link below.

Learning in RAW--
http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=3859

I would advise you make sure all the buttons are customized. The following link shows how to do this in the software:
http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=9700

If you find they are still not working, try learning each command from the original remote:
http://logitech-en-amr.custhelp.com/cgi-bin/logitech_en_amr.cfg/php/enduser/std_adp.php?p_faqid=3859

programm the remote to your tv by pressing the TV button till all lights light up at the top then enter your 3 digit tv code ( samsung codes are 738, 516 or 680 then press pound. this should enable you to controll power and volume, be sure to press sat to operate you dish recvr.

Samsung has recently acknowledged an issue with 8 series LCD TVs (e.g. LN52A860). When the TV is first turned on, it outputs strong IR interference which can render the Harmony unable to control your devices for several minutes. After the TV is warmed up, the interference dissipates and the Harmony will work correctly again.

To determine if your Samsung television is causing the issue:

1. Start an Activity that uses your Samsung TV
Confirm the Harmony is not controlling your devices
2. Completely cover the screen of your television with a blanket or dark colored sheet
3. Try changing the channel. If the device now responds, the television is interfering with your devices. Please contact Samsung for support

It is possible that by disabling certain features on your TV can also resolve the issue. Features that may cause interference with your remote include:

1. DNR/Active Control
2. Power Saving Mode

To disable either of these features, please consult the user manual for your TV.

If the volume buttons work when using the Radio, then the buttons on the Remote are fine.
Now if the volume on your TV is set to MAX and you can barely hear it.
The issue lies with your TV.. ()
Now if I understand correctly or if I am to assume you are using a Reviever.
If the reciever is used for all volumes... If this is the case.
I also assume the volume on the TV Speakers is set to off
Therefore when you use the Radio/DVD the volume control is using the Reciever volume.
and when you switch to TV it uses the TV volume thus the TV volume is not gonna work as well.
2 scenarios
1 The TV volume even at max is not giving you enough power to get the low receiver volume
2 the Receiver volume is at max and barely audible.. if this is the case just manualy adjust your TV volume to get it to a decent sound level.

Hard to explain but I know the 2 issues can be fixed.