Sudden amp death

Metalman_666

New member
TL;DR - My amp died while jamming but still powers my pedalboard through its courtesy outlet. I am stumped.

I've had my Mark IV head plugged into a Palmer PGA-04 for practice at home for about two years now. This is the Palmer with both a loadbox and the speaker SIM (ADIG-LB) and it has been great to get a direct signal to DAW when I can't plug my cab in with the bandmates.

Tonight I'm riffing along to Bridges in the Sky, running a comp and OD into RHY2. The tone is glorious. I'm using headphones coming out of my interface. Two chords into the chorus, out of nowhere, the amp just dies. All the lights go off on the head and footswitch, the sound immediately stops.

The weird thing is, my pedalboard (with PP2+) is still plugged into the courtesy outlet at the back of the amp, and the pedals all still have power. So it's like the courtesy outlet gets all the juice but the rest of the circuitry is dead.

The amp is plugged into one of those yellow Surge Master power bars, and so are the pair of studio monitors, a desk fan, and a receiver, which all still have power. I tried switching the outlet on the power bar and still no signs of life. Switching outlets, the courtesy outlet on the amp STILL gives power to anything that's plugged into it.

Before I start freaking out about this I wanted to pick your brains to see what you think the causes might be. Tomorrow or Thursday I'll take it to the only Mesa tech for miles but, am I missing something? Am I in need of a huge repair?

For the record, in the 9 years I've had this head, it's only been serviced once outside of a few full retubes. The last issue was minor in that the switching relay inside needed to be fixed, and that was 3 years ago!

Thanks in advance,

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Re: Sudden amp death

My guess is that you blew a power tube which in turn blew out the mains fuse.
Replace the fuse and power up in standby.
The amps should power on with the new fuse.
If it does and you were to put the amp into play mode you would likely blow the fuse again....
That would indicate a bad power tube.
However, since it’s only been retubed once before, you’re due.
 
Re: Sudden amp death

In all the time I've had this amp how hard I've pushed it before, I've never once had to check the fuse, so that makes a lot of sense! And yes I have certainly retubed it several times.

Attached is a pic of the fuse, I see the two little bulbs and a break in the wire so I'm hoping that's all I need. And perhaps some new power tubes?

Thanks for the quick responses guys! Any more ideas keep em coming
fbbe850220d4a2854a4c2e73f37e690f.jpg


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Re: Sudden amp death

In all the time I've had this amp how hard I've pushed it before, I've never once had to check the fuse, so that makes a lot of sense! And yes I have certainly retubed it several times.

Attached is a pic of the fuse, I see the two little bulbs and a break in the wire so I'm hoping that's all I need. And perhaps some new power tubes?

Thanks for the quick responses guys! Any more ideas keep em coming
fbbe850220d4a2854a4c2e73f37e690f.jpg


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The fuse may have died from old age. Hopefully a new one is all you need.
 
Re: Sudden amp death

Yeah, replace the fuse and power her up...if it pops again I’d think a set of power tube is in order. Any time a power tube blows the fuse is supposed to pop, so if that’s the case it’s doing its job.
 
Re: Sudden amp death

I'm glad I posted here. In my foggy state last night I didn't go straight to the fuse - I've never once had to even think about it before now, truly a testament to the reliability of Mesa!

Turns out that was it. Popped in a new 3A Slo-Bo fuse and all is well after a few minutes of high volume playing. And I now have several more, just in case.

Noob moment acknowledged, and crisis averted.

Thanks guys for the quick help and hopefully this helps someone else through the power of the web

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Re: Sudden amp death

Quick question....
You did replace it with the exact same value fuse? Correct?

Oh yes. I read the manual, checked the back of the amp, and checked the burned fuse itself just to be sure.

Still going strong and sounding great

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