Fuse burned out in shipping? ?

The above answers are intelligent discussions of what may may have blown the fuse, but none even hint at an unplugged amp blowing a fuse on its own.
08-30-12: Mechans

Mechans,

He suggested that perhaps something happened in shipping to cause the fuse to burn out!!
Aewhistory

You know the way I read that?.... The amp could have been damaged in shipment and when the buyer hooked up the amp and powered it on the fuse blew.

Doesn't that make more sense?

Aewhistory,

Is there a chance you shorted the speaker output terminals, with the connected speaker wire terminations, of the channel with the blown fuse?

Before you install the new fuse and try to power up the amp again make sure the speaker output terminals are not shorted.
Jim

Is is very common for shippers to leave things on the roof of a truck during lunch breaks and while driving slowly, thus subjecting items to lightening storms and wind driven falling power lines which can blow a fuse in an otherwise packed and sealed amp. Airplanes used in shipping get hit by lightening also, and often a criminal perpetrator is near or sitting on a box containing audio gear when being tasered. Very common, happens all the time.

It's possible the fuse got damaged in shipping from mechanical vibration. It's easy to tell if the fuse was damaged mechanically vs. was blown. Mechanically, the fuse element would be totally intact and just broke off. If the fuse blew you would see melted fuse element or charring of the element and sometimes the element gets deposited on the glass of the fuse. That being said the fuse would have had to sustain a rather large impact to break the element which begs the question, was the amp dropped in shipment?

There could be a cold solder joint at the outputs that got loosened due to shipping damage. I had a set of monoblocks sent by a complete dumb^%$ who threw them into a weak cardboard box with a few peanuts and some bubble wrap. The box was toast, a big hole in it, the amp corners were bent, a complete mess. One amp didn't work at all and he didn't even help with the claim other than to say he packed them well. I got the claim paid but it was a pain. I advise to work with the seller to come to a reasonable solution but wouldn't be happy so far. You should expect it not to be DOA. Did you use paypal or credit card? I'd ask the seller to put in a damage claim asap.

Hi guys, this is a fantastic response and I am very appreciative! It is apparent my original post left out some critical information. As I am a bit short of time I will post again, but here's what I have for the moment:

Packaging: the amp was wrapped in one very thin layer of bubble wrap and then put in a box stuffed with shredded paper. Since the box was only a bit larger than the amp itself--about 1" extra on most sides--there wasn't much room for packing material to begin with. Sadly, the shipper didn't even really stuff the box with shredded paper, so the amp could easily moved inside. So it is entirely possible this amp was damaged in shipping.

The box looked like a big ball of tape. I'm not kidding. Every inch was taped, sometimes three, four, five times over. The top of the box had caved in some during shipping, but the massive amount of tape kept it all together, so to speak. I'll take another, closer look later tonite.

As for the amp, I haven't noticed anything that I would call shipping damage. There are plenty of signs of aging, but no bent fins, dented structure, visibly broken internal parts, etc. What I DID find, though, was that is was readily apparent that this amp has had many hands inside it before. It is missing some of the screws for the top case and those that are there are different (and visibly different ages as well).

The fuse- the fuse isn't broken, it is burned. There is a lovely scorch mark in the center of the glass where it is blackened. However, I did not check this before plugging the amp in. Here is what I did:

I happened to have one speaker readily on hand that wasn't already hooked up, so I hooked it up to the left channel. Sounded peachy. Turned the amp off and waited a few seconds. Disconnected the speaker cable and moved it to right channel. Turned amp back on and never heard a peep. Turned amp back off and checked the fuses. Left channel fuse looked fine, albeit a little old. Right channel fuse looked like it had been the main course in a BBQ.

Okeedokee, so I wrote the seller about this. Meanwhile, I went and put the left channel fuse in the right holder and tried turning the amp on again. Still no sound. I went and put the fuse back in the left channel and moved speaker wire back to left to make sure that the fuse was still good. Left channel sounded just fine... Again. So this time I left the left channel fuse and put in my own fuse with same ratings. Nothing. Tried raising volume. Nothing.

One point of note: all the new fuses put into the right channel fuse holder have been fine going in and coming out. The channel isn't blowing fuses AND it isn't making sound.

Could I have crossed some wires? I hate to say never, but I feel very connfident about this. I did all of the attaching and detaching with the amp off and even allowed about 3-5 seconds for drain time. Even so I try to be sure that leads never touch because electricity can remain in the amp well after that short period. That said, I won't pretend to be infallible. What I am sure of is that I didn't check any fuses before turning on the amp. I didn't think of it although I may in the future.

I'll write more a little later, I've got to put the kids to sleep right now. Thank you all very much!

Aaron