There are also truck scales that unlike the CAT scales 3 platforms have a single long platform. It is best to go inside before you pull up to the scale and discuss with the weigh master what you want to do, usually an axle weigh for each TV axle and for the combined Trailer axles. Also let the weigh master know you don't need a certified weight - it will usually be less expensive.
Once you have the weighmasters instructions, pull around and line up with the scale. The scale I use has a red and a green light, and it will be red so you stop before moving onto the platform. On the green you have to pull the front axle onto the platform slowly and the weighmaster will give you the red when it is in position. Once the front axle weight is taken, you will get a second green, and pull forward until you get a second red - this will position both the front and rear axle of the TV on the platform. Again after the weigh is taken, you will get a 3rd green to slowly pull forward until the trailer axles are on the platform and the TV is clear, when you will get another red. Once the third weigh is done you will get a green to pull forward and clear the scale. Park and go inside to get your weights.
If you want the TV by itself, drop the trailer in the lot and drive back around and do the same thing for the two TV axles.
I've had them do the TV weigh free after I paid for the combined rig weigh, and once they gave me a second combined weigh a week later for free because she remembered that I had recently paid for one. I think it depends on the scale and how busy it happens to be.