Marshall DSL 100 fuse?

[Dazed4ndConfused]

So the other day at practice we were setting up and then EQ'ing everyone, so I after I got my rig setup I switched my standby on, and helped everyone else. About 10 minutes later when it was my turn to EQ, I flipped the switch back, and there was silence. After checking for a minute or so I found I blew my Mains fuse. We took the fuse out of our drummers amp and put it into mine, and it was good to go.

My question is, I was reading that the most common reason for blowing a fuse is a short in the power tubes? But after replacing the fuse, it works fine and I've been playing it since. So what would be the cause and solution?

[Enzo]

Ever have a light bulb burn out, and you tap on the side of the bulb a few times and the broken filament inside swinging around touches something and welds back together and the bulb works a while longer? it is a bad bulb, but still functioning.

Bad power tubes fail in a number of ways, but among them is the little tiny grid wires inside can break and start swinging around. if they happen to touch something else in there, BAM, fuses blow. But until it does touch, the tube works.

Bad power tubes is THE most common reason fuses blow, but not always the reason. Fuses CAN blow from fatigue - old age in other words. SOme other failure can be happening. Does the amp pop or crackle every now and then? That is another sign of failing power tubes.

If it is working, fine. Let it work. I'd be getting a replacement set of power tubes to have on hand though, because next time the fuse might not be all it needs to get going again. never hurts to carry spares.

[Dazed4ndConfused]

I haven't noticed any crackling or strange noises, but buying an extra set of power tubes sounds like a good idea anyway. Back to the fuse though, is there any specific fuse I need to replace it with, or will one of the same size work? And what's a good replacement tube? The DSL comes with EL34's

[Enzo]

You need to use the proper fuse, if the one that blew was original, it ought to be the right kind. It should be printed on the rear panel what the fuse it. Look right over the holder. T means "time delay" or slow blow. SO T4A means 4 amp slow blow. There are the larger 1.25 inch fuses, and there are the smaller 20mm size fuses. Get the size the holer wants. 4 amp or whatever comes in both shapes.