Light bulb problem V81

[Sodak Bob]

If I hit my switch on my 81- hold it for a few seconds - the light comes on, but only for a second or so.  I have a new bulb - which has a good rattle in it (could be broke) and I can't get any light from it...   Is this a bulb problem or something else ?  Thanks in advance

[johnieG]

if both ends of the tube light (glow) when you push & hold the switch, but the light won't stay lit, then the bulb should be good, but if the bulb has blackened ends, the ballast may be going bad & giving the bulb too much current, causing it to over heat, & shorting it's life. the other possibilty is that the push-to-start switch is going bad.

[Sodak Bob]

Yes, both ends light up when I hold the swith. And yes, the ends of the bulb are black - must be the ballast?