Just fried my Earth Original 2000. HELP!!!

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scrodzilla
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Joined: 2008-03-24
Just fried my Earth Original 2000. HELP!!!

Hello all. I've been a reader of the forum for a little while now but this is my first post.
I own an Earth Original 2000 head that just recently began giving me trouble. I bought the head used some time ago and it is, quite literally, among my favorite things in the entire world (the spot for absolute favorite often flip-flops between my Earth amp and my wife. Shhhh). I've never had any trouble besides a scratchy pot here and there until this evening. First, I blew the 5A power fuse. "No big deal", I thought as I popped in a replacement and plugged my bass back in. After only about a minute of playing, the amp started to hum very loudly as smoke appeared from the left rear corner. I shut it off, unplugged it and hung my head. Now, I am scouring the internet attempting to find information about what may have caused this. I may seem utterly naive but I've never had an amp do anything like this in the nearly 20 years I've been playing bass. I may be going apeshit over nothing...it may very well be something my local amp repair guy will be able to fix quite easily...but any light anyone reading may be able to shed on my dilemma will be greatly appreciated!

Thanks in advance.

Craig
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Joined: 2007-12-05
Smokin'

scrodzilla,

Sorry to read about your amp. Fortunately, those great hand-wired amps make it much easier to repair, not to mention troubleshoot.

Anyway, you asked if anyone has ever seen that happen before. Well not to my Earth 2000, but I have a Fender Acoustasonic amp that I literally smoked. I was jammin' away when smoke billowed from behind my amp. Of course I turned it off.

What literally caught on fire was a 2 watt resistor in one of the power amp push-pull circuits. I was not about to take it to a tech unless I absolutely had to, so I took the thing apart to examine the damage. A friend of mine came over with his O-scope and we started searching for the rest of the problems. There were two bad transistors and two bad 1/4 watt resistors in the same circuit. The problem is, when the circuit let go, full push-pull circuit voltage (+/- 56V) was sent to two of my speakers, smoking them as well. Total cost to me was around $5 for the electronics, $80 for an 8-inch speaker, and $15 for a tweeter. However, because it had been a while since I had used an O-scope and because it had been a while since he had scoped out an amplifier (especially a modern one, with built-in effects, etc.), it took us around 4 hours (8 man-hours) to get to the point where we were totally satisfied with the result of our venture. However, I have the satisfaction in knowing more about my amp than I did before.

Personally, I think the hand-wired amps are easier to repair, seeing how one does not have such little space to work with. Things are spread out better then they are in a modern solid state amp like the one I described above.

Pull the power cord out of the wall and then remove the amplifier chasis and look for the source of the fire. It will be obvious where it started. This will give you an idea of how many components will be immediately considered for replacement. Unless your an electronic hobbyist or a technician, I would not go much further than a visual inspection of the electronics. Next, plug your speaker cab into something that works and make sure all your speakers are still good. Plug your bass into the amp's clean channel and make sure there are no effects. Listen to each speaker: Obviously, if nothing comes out of any or all of the speakers, or if your bass sounds scratchy through any of the speakers, consider them (or the one that is producing no tone or a bad tone) gone.

My amp just gave out on me as well this week as well (but no smoke). However, I believe it is tube-related. Thank the Lord for tubes!!! Pop one out and pop another in. But I'm changing them all at once to ensure their common duty time.

Good luck in your troubleshooting adventure.

Happy Earth Super Guitar G-2000 Owner

scrodzilla
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Joined: 2008-03-24
Hey Craig...thanks very much

Hey Craig...thanks very much for your response. I have very little knowledge of electronics but I did take the chassis apart and can pinpoint the area where the problem occurred. I have tried and tried to locate a schematic for this amp but have had no luck whatsoever. It looks fairly simple inside. There's a very reputable amp guy nearby and I will most likely be bringing it to him in the near future.

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