Eminar 'Apollo 160' blowing fuses

[onorato]

So I just bought this Eminar 'Apollo 160' which according to my research was built in the 1970s. When I first played it at the guys house, it was awesome. There were heaps of crackles, but that was just my shit lead. One time, the crackles from my lead got big so I flicked the volume down possibly a bit too hard than I should have and I think then was the first time the fuse blew. I went out and bought some more fuses. 250v 3A fast blow.

When i put in the new fuse, and turned it on, "POPGGGGGGGGGG fuse blown". I'm thinking maybe I loosened a wire when i flicked the volume down. I've tried 3 new fuses and all of them have been the same. Any ideas what it could be or who I could send this amp to?

[R.G.]

Flipping volume knobs around does not kill amps that are otherwise good. It was a coincidence that the amp was already near failure.

From your post, I take it you're not skilled enough to dig into the amp yourself. About all a non-tech can do on an amp is replace fuses and tubes. Is it tube based? If so, go read "The Tube Amp Debugging Page".

Otherwise, find a good tech. Speculation on what problems it has won't do you much good, as it could be any number of things.

[olddawg]

That looks like a solid state amp. Does it have big TO3 output transistors on the back panel or an internal heat sink? If so, you probably connected it to a bad load and shorted out the output transistors. If this is the case turning the amp on and replacing fuses to blow again can keep causing more and more damage to the driver transistors, bais resistors, etc. You are drawing major current somewhere.

[onorato]

About the flipping volume knobs. A friend of mine said it could be a loose wire. I'm thinking maybe when I flipped the volume knob, i knocked something inside which may have moved the wire. And yes, it is a tube amp. Not sure what the T03 thing is, but I'm pretty sure it hasn't got one. Can anyone recommend any good amp repair places or people?

Also, I read somewhere online that if you open a tube amp, even if it has been disconnected from power for a few days, you can get a shock from it and die? Or are they just saying that to scare people so they take it to them and get money?

Thanks for the quick replies.

[R.G.]

About the flipping volume knobs. A friend of mine said it could be a loose wire. I'm thinking maybe when I flipped the volume knob, i knocked something inside which may have moved the wire. And yes, it is a tube amp.

Put it this way. Any wire which could be knocked loose by flipping a volume knob is already broken, unless you used a hammer to do the flipping. I'm guessing that your friend doesn't have a lot of experience with amps either.

Even if it were just a loose wire (that is, a broken wire) then it would need to be soldered back in to position and restrained so it doesn't break again. This involves touching the internal parts of the amp, about which see below.

Can anyone recommend any good amp repair places or people?

That depends on what part of the world you're in, and whether you want to ship the amp to Timbuktu. There are competent repair places in all USA cities of any reasonable size. That's not true in the rest of the world, though.

Also, I read somewhere online that if you open a tube amp, even if it has been disconnected from power for a few days, you can get a shock from it and die? Or are they just saying that to scare people so they take it to them and get money?

In this case what "they" said is correct. If you don't already know how to work safely inside a high voltage tube amp, then you are at significant risk of getting shocked and possibly killed. There's also a risk that if you don't know the right way to do repairs you set up a situation that can kill you or someone else years later when circumstances conspire the wrong way. Or cause a house fire. Or just burn up (as in flames and smoke) your amplifier.

No amp is worth taking a chance on dying for.

[Enzo]

The voltages inside these amps can KILL YOU in an instant. I doubt the capacitors remain charged for several days, but it never hurts to check with a meter before working inside. I freely spend hours here every week helping guys repair their own equipment, so I hardly think I tell people to be careful to scare them into my shop. And that is what I do for a living - amp repair.

I don't care how loose the volume control was, it is just real unlikely it caused blown fuses. What is far more likely other than simple coincidence, is when you spun your control, the mechanical vibration from you hitting the control was enough to push an already failing power tube over the edge.

People worry way too much about "Oh no, I did something to my amp." Things have to fail sometime, and that is usually while you are using the amp. SO when it blows up, you were bound to be doing something, but that something was probably not the cause of the failure.

Pops and crackles are a common sign of failing power tubes. One wonders how old your power tubes are in that thing. A new set of power tubes is a good idea on any used gear purchase.

[Enzo]

Ooooh, a simulpost.

[Chuck H]

"Simulpost"...Simulpost... I like it. I usually oppose the coining of phrases, but I'll make an exception.

Onorato, go here:

http://www.aikenamps.com/SafetyTips.html

Lot's of great info at the home site too, for anyone looking to poke around in an amp.

Chuck

[Enzo]

I can't take the credit, that term has been bouncing around a number of forums I frequent.

You might be interested in joining my wife's organization then. it is called SUSAN, for Stop Using Stupid Acronums Now. I think Steve C is already a member.

[onorato]

Thanks for the help so far guys. I've been looking around other places that have suggested removing all the tubes and then turning it on. If the fuse doesn't blow, it's a faulty tube. I tried this before and the fuse didn't blow. I'm not sure whether I should buy a new tube and try my luck, or take it to a repair shop in case I just end up breaking another tube. It'd probably be better if I took it somewhere, but I don't think I can wait that long so I might just buy a tube tomorrow unless someone can talk me out of it.

EDIT: I just talked to one of my friends dads, and he said to try it again with all the tubes except the burnt out one, and if it doesnt blow a fuse, then it's that tube. So i did that and the fuse is fine I think im off the buy a tube