Blue Convergence just went out?
High Voltage Capacitor? Leave the set unplugged for 1/2 hour most components will selfdischarge, as for your problem, being a Magnavox, you have one of two problems, the convergence I suspect is what is blown out, this unit probably uses STK392-110 Ic's, I would suggest replacing with STK394-160e chips as they are probably shorted, some of the big resistors (1 or 2) may be opened up also, usually they change color. The only other thing that would cause usually a yellow color in the corners is the CRT Fluid, it changes from clear to Orange in color and clamps off the blue color from the fringes, I suspect the chips need replacement, dont forget to put some heatsink dope behind them, they are usually on the left in the front of the set (from the back) Big long heatsink that is fairly tall (probably the biggest heatsink in the set.) Good luck, and the repair usually runs around $350.