confused by my fuse

[I Eat Winos]

hello boogie board...Im ever so new here....and you fine people are my brand new internet buddies...how lovley. We can go off and frolic and play loudly then tell tales of our exploits...

so I've been brought here by my fuse. I have a mesa boogie mark 3 redstripe. Just put new tubes into it (5 tung sol 12ax7s, a pair of mullard el34s and a pair of sed winged C 6L6s) and it blew a fuse on me. Had it turned around backwards, didn't see the tubes glow crazy red, spark or anything. Didn't here any crackling or anything. Any idea what could have caused the fuse to blow. I've been told possibly a brown out or a power spike. Any ideas?

 

[disassembled]

Are the power tubes new or used? Tubes can be damaged quite easily so you might have bought some duds. The first step you should do is to remove the new power tubes and replace the fuse. Turn the amp on without the tubes plugged in and see if the fuse blows (you only need to do this for a second so don't try and play the amp this way). If the amp operates fine put in the old power tubes and power the amp up again. If the fuse is good and the amp works as normal then you have 1 or more bad tubes and should return them for a refund/exchange.

I am almost positive the preamp tubes are not causing the fuse to blow but you never know. Also, you have to be careful to make sure all 4 of the old tubes glow blue when you pull the amp out of standby otherwise, you may have damaged some components inside.

Try this out for starters and then get back if you need some more help.

Greg

 

[I Eat Winos]

hey greg thanks for your help. All the tubes are brand new. Replaced the fuse. Turned on the amp with the power tubes out and it ran fine. Unfortunately I don't have old power tubes to put in...one of them went out on me. Anyways the amp ran for about a day and a half before it the fuse blew. I put the new tubes back in and its running normally. They have a lovely blue glow when I pull the amp off standby. So i remain confused. Nice name by the way. I am a greg as well.