Need Help w/ Mesa head

[Bixby]

I'm new to these forums but need your help... Over the Christmas holidays my best friends 6 yr old boy found his way into my den and turned on my Mesa 3x recitifer head... it wasn't plugged into the cabinet... I came in aprx 5 minutes later and smelled that scary burning electronics smell and traced it to my amp. The fuse was blown but I am wondering what damage has been done? I never have had the head disconnected from the cabinet before and it was strictly coincidental that I left it unplugged this time. I have no idea what the potential ramifications may be. I passed it off as harmless at the time because he's a great friend and I adore his son but I haven't slept a wink since.... any input would help me get some rest until I can get it into the shop (I don't do electrical stuff....!)

Thanks for your input! Happy New Year!

[Fragger]

Some discussion of similar problems here

[mikeboone]

Running a tube amp with no load is bad. I have seen OTs go south and I have seen it cause serious arc'ing in the tube sockets but sparing the OT.

A triple rectifier (all Mesa's) is a really complicated beast. You are best served by sending it to a qualified Mesa repair shop or to Mesa directly.

Your best bet is to never have your head plugged in without a load.

[tim]

Have you replaced the fuse to see if it still works? It's possible that the tubes got hot and that's what you were smelling and the current through them without a load was high enough to blow a fuse. Try another fuse, turn amp on for a couple of minutes (on standby) and see if fuse blows...if not, take amp off standby, and see if fuse blows. If so, you might simply have a cooked/shorted power tube (pull power tubes out and try again, replacing fuse if necessary...if fuse doesn't blow with tubes out then one or more of your tubes are shorted)...if the amp stays on, keep an eye on the power tubes for a couple of minutes to see if any red plate. If any do, and you're not used to working inside an amp, it's best to get it to a qualified tech...if tubes are happy (not red plating), then you're probably OK...chalk it up to experience...and replace the power tubes that were in there, just in case.