2:90 help VERY needed

[welldressedbob]

I recently baught a second hand 2:90. The smartass who sold it just rapped a box around it and shipped it. ABSOLUTLY NO padding
or protection whatsoever. So naturally it got banged up. A dent here and there, and the sides where the inputs are got bendt. I inspected it and tried to listen for ratling objects inside and broken tubes. I found nothing.

Then i plugged it in. It was firing up as normal and there was sound in channel A. All the mode switches worked to. Then when i turned on channel B there was no sound. I tried turning it on standby and the on again. The channel A tubes flashed and started glowing bluish. The B side tubes barely made a flash and didnt glow blue. Then after 10 seconds a burning smell appeared . There was sound from channel A all the time. I switched off and then pulled the top cover off and inspected the innards of the amp. I noticed a connector was slightly melted. I pulled the channel B fuse too, and it was blown. The A was OK

Here is a close up, and a overview shot of it.

 

[samhill]

That's more than slightly melted. I would take it to a good tech...he may just have to replace the connector, but more likely is that something has gone faulty to cause the connector to melt like that. As bad as it looks it's probably not too serious. But I wouldn't power up anymore...just take it in to get fixed or you may cause even more damage.

Mark

 

[welldressedbob]

Yeah, i will do that. Then all i have to do is find a good tech. They dont grow on threes in my country...

 

[luigi]

It's possible that the output section lost its bias (assuming the output tubes are good and not the cause themselves). That could make it go crazy and draw a ton of current....causing the meltdown and the blown fuse.

Very best thing to do.....in fact, the only real thing to do is what Samhill suggested, have it looked at by a good tech.

-Luigi

 

[Sanchez]

welldressedbob

What country are you from?

 

[jesper]

I don't no if you are from the States, but I have an original 117 V trafo for the 2:90.

It's a leftover when I replaced it for a 220 V trafo. Let me know if it a 117 V trafo you are needed.

 

[welldressedbob]

Thanx for your inputs guys. Im from Norway. I trying to look up a amp tech, but as i said its hard. None of the guitarstores ive called even have a amp tech. Or a person that is qualified to do regular maintenance on tube amps.

 

[jesper]

Hi welldressedbob,

It seems to me that the guy who sold you the amplifire have try to do some repair on the amplifires power supply. I can see from the picture that a part of the connector is missing and the wire is soldered directly on the pin, maybe on the wrong one which may have cause a short.

Use should find a new connector and replaced it. This not difficult.

You can mail me for futher questions and I will try to help you.

BR
Jesper

 

[Boogiebabies]

It's possible that the output section lost its bias (assuming the output tubes are good and not the cause themselves). That could make it go crazy and draw a ton of current....causing the meltdown and the blown fuse.

Very best thing to do.....in fact, the only real thing to do is what Samhill suggested, have it looked at by a good tech.

-BT

Very nasty. If the fuse did not go, I am sure the OT did. The HV supply looks fine, but the bias and heater supply look cooked. The bias caps and resistors all look fine though.


I would send it right to Mesa regardless of the cost or return it to the seller.

 

[Jman69]

Don't worry too much, theres probably nothing wrong with your unit other than that melted connector. I had the same problem three months ago, as i'm sure many 2:90 owners have in the past. It's a production fault. In order for Mesa Boogie to manufacture a great deal of units they must compromise, so instead of wiring to the board they use a small plastic connector. This has no effect on the tone, but sooner or later that thing is going to melt. I would not be surprised if many of the guys who rely on these amps for gigs and tours have already performed a mod to that part of the circuit.

 

[luigi]

That's a pretty big probably. I wouldn't turn that rig on again until it was at least checked over by someone that knew what he was doing. This is a major blunder on Mesa's part if this is a common problem with these amps and should of been caught and remedied @ the factory.

No amplifier in any production should melt like this....AND no consumer should ever buy any amp and expect this to happen at some point.

 

[Basterd]

Thanx for your inputs guys. Im from Norway. I trying to look up a amp tech, but as i said its hard. None of the guitarstores ive called even have a amp tech. Or a person that is qualified to do regular maintenance on tube amps.

Hi,

Any news on "the problem" with your amp?! cause when i opend my 2:90 i had sort of the same problem, the first 2 pins of the connector from the right, on your picture, is melted and black. :shock:

I had ordered new tubes cause i had bought it secondhand and it didnt sound that good, mainly channel B, and now this but the amp did work, both channels.

Maybe you have your amp fixed allready, could you tell me/us what is was and so???


Wish me luck, cheers....... :roll:

 

[Henz]

These amps need recalled!!! They marketed a product that clearly has many issues!!