Well, the easiest way is to get a multimeter, set it to diode test, and measure between the two legs and then each leg and the outside casing. If you get a beep or zero reading, it is bad. Make sure you unplug the the connector to the deflection board before doing so, as you may get a false reading through the board.
If you don't have a meter, you could always swap one 2N3716 with the other 2N3716 and see if the problem changes. If so, replace the bad one (or both if you can't figure out which is bad). If no change, swap the 2N3792's and check again. I usually change out all four if I have a problem with one.
Sometimes, you may find that the transistor that is in there, doesn't have the 3716 or 3792 markings. If that is the case, report back on what you have...