Bugera 6262 combo..here I go again

[Pino]

Hi guys, I was rehearsing with my band yesterday and suddenly my Bugera 6262 combo turned off. The amp didn`t made any weird sound, no burning smell, just stopped working. With my little knowledge I checked the back fuse and it was ok, then looked inside the amp and tested the four fuses of the (I guess) the power supply section and they were fine too. After spending 15 minutes looking carefully the board and connections and don`t see anything wrong, nothing look burnt, out of place, etc.... I have two gigs next week and I`m pissed. Any suggestions? Please keep the Chinese crap for you, I love the sound of this amp..

PS: The amp is 1 1/2 years old so no warranty here. I`ve changed the crappy Bugera tubes for a new set of JJ`s about a year ago and they worked great until yesterday.

Thank`s in advance for your help.

[Enzo]

Stopped working as in no sound but the lights are on? Or stopped working as in the amp went dark as if unplugged from the wall?


If the whole thing went dark and the fuses are OK, look at the small circuit board where the main AC power cord connector is.

I think you are looking at the solder side of it when looking into the amp. Look VERY closely at the solder conections on that board. I bet you have one cracked. If you pull the board out, you would see a number of discs soldered on edge to the board. Four or them maybe? They are thermistors wired in series. They serve as inrush limiters. They like to crack free of their solder. A quick resolder of them, and the amp is good as new. I'd wager that is what happened.

[Pino]

Stopped working as in no sound but the lights are on? Or stopped working as in the amp went dark as if unplugged from the wall?


If the whole thing went dark and the fuses are OK, look at the small circuit board where the main AC power cord connector is.

I think you are looking at the solder side of it when looking into the amp. Look VERY closely at the solder conections on that board. I bet you have one cracked. If you pull the board out, you would see a number of discs soldered on edge to the board. Four or them maybe? They are thermistors wired in series. They serve as inrush limiters. They like to crack free of their solder. A quick resolder of them, and the amp is good as new. I'd wager that is what happened.

Thank`s for the response Enzo. The amp turned off as if was unplugged from the wall, none of the lights are on. I will check the board right away and let you know.

[Pino]

I checked what you told me but I don`t see anything wrong below are some photos:







The board:

[Enzo]

Hard to see from here, but look at the second photo, the photo of the solder side. On the center of the board, more or less, is a small "L" shaped trace, directly above the white sticker. There is a component lead soldered into each end of that L. The one at the top looks like a bad solder joint to me. Actually so does the joint right above the first "R" on "Primary".

SO there are six thermistors instead of four - close guess anyway. The green discs. Just resolder all of them. As you solder each, hold them from the other side to make sure the lead sticks through the hole in the board. SOmetimes the lead is a bit corroded, so I scrape a clean surfacce on the leg for soldering with a razor blade or Xacto blade.

[Pino]

Do you think it could be the transformer?

Thanks`

[Enzo]

No, I don;t think it is the transformer, I think it is a failed solder connection as I pointed out. Did you try resoldering ALL those green discs? It will only8 take a few minutes. DO it just to make me happy. If it solves the problem, then you will be happy too. And if it does not solve the problem, then at least we know that the soldered discs won't be a new problem next week.

[Pino]

Ok I`ll do it. But I was just wondering if the transformer was the one who caused this issue. Let me re-solder the green things and I`ll let you know.

Thank`s again man

[Enzo]

The thermistors work by starting out at one resistance, then heating up and dropping their resistance. They get hot as part of their job. SO they are constantly thermally cycling hot/cold/hot/cold. The thermal expansion can crack the solder. That plus vibration. The transformer would have nothing to do with this, other than the current to it flows through the greenies to get there.

I of course can;t guarantee that is the problem, but just about every Bugera head that comes through my shop for "dead" has that solder broken.

[Pino]

The thermistors work by starting out at one resistance, then heating up and dropping their resistance. They get hot as part of their job. SO they are constantly thermally cycling hot/cold/hot/cold. The thermal expansion can crack the solder. That plus vibration. The transformer would have nothing to do with this, other than the current to it flows through the greenies to get there.

I of course can;t guarantee that is the problem, but just about every Bugera head that comes through my shop for "dead" has that solder broken.

Dude you are the man. as you pointed out one of the thermistors was loose the one right above the first "R" on "Primary". I`ve just moved the green disc and there it was!!! I haven`t solder it yet cause I don`t have the right tools but I`ll let you know later when I do it.

Thank`s a ton!!

[Enzo]

The one at the top of the L is OK?


DO yourself a favor, resolder ALL of the green disc leads. Even if they look great.

[Pino]

The one at the top of the L is OK?


DO yourself a favor, resolder ALL of the green disc leads. Even if they look great.

The "L" shaped was OK but I followed your advice and re-solder all of them. The amp is up and running again and I`m extremely happy man you saved my life here .

I really appreciate your help Enzo thank you so much

[Alex R]

I still think it was the transformer.

(just kidding)

[Steve Conner]

Everyone thinks it's the transformer.

[Alex R]

Yay brother, oft-times, that ol devil, he hunkers down on my shoulder and this is what he say:

"Hey solder boy, take my advice, whoever comes through the door, you just purse your lips at 'em and make that whistlin' noise I taught you, and shake your head and say, Sorry mate, it's your transformers. Then their eyes will widen with good ol'fashioned self-congratulation and lo, they will all be like, "I knew it!" Then you just spray switch cleaner in the effects jacks like always and charge them 200 quid a go. And ain't that righteous!

But I know he's a-thinkin, and then your soul will be mine, mwa-hahaha, and I say, devil, I defy thee! - and down he hops, till the next time.