Ho do you tell if a round metal end ceramic fuse is bad? Also a round metal end glass with metal fuse with a ball on it model 51MS? I have a Toshiba theatrewide hdtv flat panel that doesn't power up sometimes and always has no picture?

 

If it powers up sometimes the fuse is probably good. You can check a fuse with an ohm meter or a continuity tester.A good fuse will show continuity or a low (less than 1 ohm) resistance with a meter.

edit: The fuse should be checked out of the circuit for an accurate reading.

 

A 51MS is an axial cartridge type "Medium Slow" fuse, about 20mm long by 5.1mm diameter. There should be voltage and amperage markings on the fuse as well.

Unplug the power from the mains before proceeding.
You need to use a multimeter set to Ohms, or a continuity tester, to test the fuses. Remove the fuses from the circuit before testing.

A "good" fuse will have very low resistance (under an Ohm).