Burnt something inside my LSC

[rabbittesticles]

I have been switching my extension cab back and forth from my classic to the special a lot lately. The other day i noticed a burning smell coming from my classic. I switched it off quickly and noticed that I had accidentally plugged the extension cab (16 ohm) into the far left jack instead of the middle like i usually do. I have played it since and there seems to be no problem with it..but when I opened her up and looked inside I found this :

anyone know what these are, or if they can be replaced?

thanks

 

[oldlefty]

Well, since they say 2.75k ohms, I'd guess they are resistors.

 

[plan-x]

I agree but.... the board looks damaged. Watch out for those big blue caps right next to em. If they're not drained they can zap you.

 

[handyandy]

By far left socket you mean the 8ohm?
Mesa boogie states in the manual that plugging a 16 ohm cab in the 8 ohm output is a "safe mismatch"
I have a 16 ohm 2x12 cab which I plug into the 8 ohm and plug the combos speakers into the 4 ohm, I thought I smelt burning also but everything works fine and I haven't been inside the amp to check, perhaps I should be worried?
Again it clearly states in the manual that it's safe to do this.

 

[rabbittesticles]

hmm..

I downloaded the lonestar manual and it looks to me like you are only supposed to plug a single 16 ohm cab into the middle jack or the jack to the right. It does not show a picture of a 16 ohm cab plugged into the left jack .. I'm looking at diagrams 4 and 5 on page 27.

I dropped my amp off at the guitar shop today. The tech said he would call me back about it once he spoke with their mesa rep. He said it didn't look good though..

 

[rabbittesticles]

Ok upon review I found this too :

When running a higher resistance ( for example: 8 ohm output into 16 ohm cabinet ), a slightly different feel and
response will be eminent. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is
a result of the amplifi er running a bit cooler. Sometimes when using more than one cabinet a mismatch will be the only option.

now I have no clue why the resistor burned up...man.

 

[handyandy]

I'm not sure either but I'm interested to here what the tech/Mesa says!
Hope you get it sorted with no hassle!

 

[plan-x]

The way any amp's ohm rating works is what the lowest ohm it can handle safely. The Lonestar can handle 4 ohms safely period. Regardless of what the jack says. 16 ohms isn't going to hurt the amp. If you screw up and run below 4 ohms or no cab at all...then there is a price to be paid.

 

[rabbittesticles]

talked some with my extremely slow moving amp tech the other day. he said its gonna be around 5 hours of work and about 300 dollars to dremel off the burned area and replace the resistors...

not sure if i should take it somewhere else and get a second opinion on it..

frustrating though, its been about a month since i've seen my baby.. and while it's in the shop i'm considering going ahead with the bias mod too..

 

[plan-x]

That's a tough call. You better get a guarantee in writing that that amp will work after that. LSC's are worth a grand 2nd hand, and less with board damage. Maybe 700-800. 300 is getting close to the"half rule". If it costs more than half its replacement value to repair it. Then replace it. Might as well repair it rather than write it off. Especially if you paid alot for it.