Is it a duet or a quad? If it's one tube out of a quad, then it might be working at half power and you haven't noticed. Or, you just might not be able to see the filament from your angle - they're not always easy to see.
If the filament is truly not glowing, there ain't not way the tube is working.
Is it a duet or a quad? If it's one tube out of a quad, then it might be working at half power and you haven't noticed. Or, you just might not be able to see the filament from your angle - they're not always easy to see.
If the filament is truly not glowing, there ain't not way the tube is working.