God fucking dammit, my XSr took a crap on me

[Metaltastic]

Yesterday, I rolled my stack over to an outlet with the hopes of getting my tube fix for the day. I plugged in, and flipped on the power switch, letting it do its warm-up thing. While waiting, I noticed what I would describe as a "flicker;" it seemed to shut off and then back on quickly. "Whatevs," thought I, "just a dip in the power." Well, after a little while longer, I flipped the standby switch up - and off goes the amp, just like that! No noise, no smoke, it just made the same sound it would if I were to turn it off the normal way, except now it won't even turn on at all.

So a few details. I've always made sure the impedance was set to 8 ohms connecting to my Bogner 2x12, I've never turned it on without the cab connected, and I'm using a 12-gauge Planet Waves speaker cable. So it's not that. I have the full KT77 retube kit from eurotubes, as well as a bias probe/multimeter, which I used to bias it at 38 mA. This is well within the operating range, so I don't think it's that either (I've never seen what a "blown" tube looks like, but seeing as how the power tubes look totally fine and there wasn't any kind of sound when it shut off, I'm pretty sure they're fine).

The other day I did have it in the studio and cranked it to about 1 o'clock on the ultra channel volume and the master for recording, but for chrissakes, this thing has gotta be able to handle that much! Also, I had never looked at the fuse before this, so I don't know what it looked like then, but here's a pic of it now (I've never seen a blown fuse before, so this might be that, or it might've always looked like that).

But that doesn't really solve my problems, cuz the fuse only blows when something else is wrong, right? Any help anyone could be would be much appreciated! I'm gonna pull the chassis out later today and look for anything atypical.

 

[ochants76]

Thats a blown fuse. Check for loose connections internally. Don't be afraid to call or email peavey. They are pretty helpful.

 

[JeffTD]

That fuse looks like it has some sort of coating on it, like they don't want you to be able to tell if it's blown or not? Weird.

Anyways... ochants nailed it.

 

[2012]

swap out the tubes with whatever was in there before and replace the fuse.

just to see...

 

[Metaltastic]

Thanks dudes, I figured that was the case (though it seems odd how uniformly gray it is; I did a google image search for "blown fuse" and the ones I found looked kinda smoky; this, on the other hand, looks like it was painted that way from the inside). I emailed both Peavey support and Eurotubes yesterday when it happened, but it's 11:30 AM on Sunday morning here in the Eastern Seaboard, so I can't expect an answer until tomorrow. Here's a couple of pics of the chassis; I have no freakin' clue what to look for, but it all looks ship-shape (though I'll get to scrutinizing it in a bit).

Also, do you happen to know what kind of replacement fuse I should buy? And these actually were the tubes that came with it when I bought it from ebay.

 

[006]

This happened to me the other day when I was rebiasing my XSr. The fuse that Peavey puts in there is a ceramic one. A regular glass fuse will work just fine, I bought a 5-pack of them from the local RadioShack. Get the 5-amp 250-volt SLOW BLOW fuses. Make sure they are SLOW blow.

I replaced mine after it unexpectedly turned off while rebiasing...I figured it was the fuse but when I took it out I was like, "fuck, how do I tell if it's really blown..." Got the 5-pack and replaced it, sure enough it was the fuse. There is nothing special about ceramic fuses...no advantages over glass.

~e.a

 

[egan.]

That fuse looks like it has some sort of coating on it, like they don't want you to be able to tell if it's blown or not?

It's just ceramic instead of glass. They're white when new and turn brown/black when blown.

 

[Metaltastic]

This happened to me the other day when I was rebiasing my XSr. The fuse that Peavey puts in there is a ceramic one. A regular glass fuse will work just fine, I bought a 5-pack of them from the local RadioShack. Get the 5-amp 250-volt SLOW BLOW fuses. Make sure they are SLOW blow.

I replaced mine after it unexpectedly turned off while rebiasing...I figured it was the fuse but when I took it out I was like, "fuck, how do I tell if it's really blown..." Got the 5-pack and replaced it, sure enough it was the fuse. There is nothing special about ceramic fuses...no advantages over glass.

~e.a

Thanks dude, that's extremely helpful! I'll head over to my local RS first thing tomorrow and grab a set (just out of curiosity, why the Slow Blow models?). Still, though, doesn't a fuse only blow to protect the amp when something else is wrong? I can't imagine what it would be, cuz I've babied this thing, but still, I wouldn't wanna just stick a new fuse in there if the problem was bigger than that.

 

[colonel kurtz]

shit, man...be glad it's just a fuse at this point

something similar happened to my amp a while ago, and it ended up being the power transformer that toasted

 

[ochants76]

Power transformer is very much a possibility. If the fuse blows again that is most likely the problem. Fuses can blow without a complete failure of something else. They constantly have voltage on them and they can go bad. Sometimes a random voltage spike can happen and take out a fuse. One of the first diagnostic tests I do with a blown fuse is....see if a second fuse blows.

 

[006]

Ochants explained it best. Fuses can actually blow for no apparent reason, due to voltage spikes or just a matter of a worn out fuse. However if you are constantly blowing them then you definitely need to have your amp looked at. See if a new fuse blows, if so, take it into a shop.

I forget exactly why you are suppose to use slow-blow fuses...but I do, for a fact, know you really don't want anything else in there. I think, as the name implies, it blows slower than a typical fuse, which I'm sure protects one or more of the components that are in the amp. Like I said, I don't know exactly why, but that's all I've ever been told.

~e.a

 

[Metaltastic]

Haha, fair enough man, I doubt it makes that much of a difference so I'll take your word for it and go for it, thanks! We shall see whether a replacement one holds up...

 

[JBroll]

A quick way to make sure the fuse is the problem is to wrap it in foil, replace it, and pay very close attention when you start it up. Always assume that the fuse blew for a reason, and use the foil trick to make sure it is a fuse and not something else.

Jeff

 

[Metaltastic]

I've never heard that before dude, could you elaborate? What exactly am I looking for, and are you saying to wrap the whole fuse in foil, contacts and all?

 

[::XeS::]

But...why your fuses (metalstatic and elephant) blow after the reamp? You have the same amp....probably a bigger current can blow the peavey's fuse

 

[Nebulous]

See what happens to the XSr's-
Should have bought the JSX!!

 

[hsinn3r]

I've never heard that before dude, could you elaborate? What exactly am I looking for, and are you saying to wrap the whole fuse in foil, contacts and all?

he means that if you wire the two ends of the fuse "slot" in the amp (or wrap the fuse in tin foil), it should work. but only do it to check if it is the fuses fault, don't keep the amp working without a fuse, or else...
get well soon XSr!

 

[kev]

I've never heard that before dude, could you elaborate? What exactly am I looking for, and are you saying to wrap the whole fuse in foil, contacts and all?

Its so it will conduct the electric lol

 

[Metaltastic]

Well I went to RS today and got the 5A 250-volt slow-blowers, stuck one in, and so far so good. So only time will tell...

 

[::XeS::]

What do you think about these KT77s? Better than EL34s?