When you are working on the Horizontal section of a TV set, remember that the plate pin or plate cap of the HO tube has RF on it.
Now getting shocked by it is bad enough, but the resulting RF burn will hurt like the devil and may take 3-4 weeks to heal. Just because the HO tube may have an insulated plate cap on it, does not mean that you won't get shocked/burned by the RF. The insulation on the cap can crack or fail, and not be readily visible.