#1
Yo dudes,

First, here's my setup:


Guitar -> Boss GT-8 (preamp) -> Mesa 50/50 (power amp *BROKEN*) -> Speakers (2x12 8ohm)


About two days ago, I went and played some music with a friend for about 4 hours, and then brought my gear back home. Once I was home, I plugged in everything and the fuse of the power amp blew out. Fun fun.

I went to the store today and bought a pair of new fuses (3A 250V Slow Blow(lol)). I installed the new fuse, and the turned on the amp (after letting it sit on standby for about five minutes). One of the tubes started sizzling and smoking (not a feature).

How do I fix this without having to bring it to the amp repair shop?
Guitar rig
Schecter C-1 Classic
Boss GT-8
Mesa 50/50 Power Amp
Avatar G212H 2x12 Cab

Synth Rig
M-Audio Oxygen 61
Creative Sound Blaster X-Fi Elite Pro
Reason 4.0
FL Studio 8
#2
how old are the tubes?

i'd try changing them out first and see what that does.
Guitars:
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amps:
Bugera 6262 212 loaded with WGS veteran 30's
#3
Quote by Gundamnitpete
how old are the tubes?

i'd try changing them out first and see what that does.


They're about 3 years old. I have some spare Mesa 6L6 GC STR 430. The ones in the amp are 4 Mesa 6L6 GC STR 440. Can I mix these up?
Guitar rig
Schecter C-1 Classic
Boss GT-8
Mesa 50/50 Power Amp
Avatar G212H 2x12 Cab

Synth Rig
M-Audio Oxygen 61
Creative Sound Blaster X-Fi Elite Pro
Reason 4.0
FL Studio 8
#4
I lol'd at the "not a feature."

Anyway, maybe try the other fuse, cuz maybe that one was bad, then check the tubes. Could something have gotten in onto the tube? Like a bug or something stuck in there that got lit up when you fired it up?

EDIt: Well at 3 years old you'll probably need new tubes soon anyway, but I've never had a bad tube smoke on me...
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Last edited by racman92 at Apr 26, 2011,
#5
sounds like the tubes are bad. check them for arcing, and replace asap.
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#6
Smoke? That aint coming from the tubes themselves. You'd have to have a major, major vacuum leak for that - it just doesn't happen. I would examine the entire amp for scorch marks before doing anything. DON'T just plug in new tubes and hope for the best. If you don't know what you are looking at, take it to somebody that does.
Gilchrist custom
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Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
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Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
Yo dudes, forgot to mention. The smoke was mostly coming from the blown tube. But the tube definitely sizzled/arced and smoked a bit. Maybe some dust caught fire or something.

EDIT: I just plugged it back in, just for fun. It is definitely arc'ing. Shieet.

EDIT v2:
Quote by Cathbard
If you don't know what you are looking at, take it to somebody that does.


I'm not exactly sure what is failing but I know the basics of electronics, and I'd like to learn. It looks as if the sparks are only happening near the connectors of the tube (sparks only happening on one tube).

Any ideas?
Guitar rig
Schecter C-1 Classic
Boss GT-8
Mesa 50/50 Power Amp
Avatar G212H 2x12 Cab

Synth Rig
M-Audio Oxygen 61
Creative Sound Blaster X-Fi Elite Pro
Reason 4.0
FL Studio 8
Last edited by Cynoxx at Apr 26, 2011,
#8
Or you burned out the wiring at the socket or the socket itself burned out. Either way, you should be checking these things out before proceeding.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#9
Quote by Cathbard
Or you burned out the wiring at the socket or the socket itself burned out. Either way, you should be checking these things out before proceeding.


Yeah, looks like it.. There's no obvious burn marks but there definitely is something wrong in that region.

EDIT: Upon close inspection, there's a cooked resistor. I'll post a picture in a minute.
Guitar rig
Schecter C-1 Classic
Boss GT-8
Mesa 50/50 Power Amp
Avatar G212H 2x12 Cab

Synth Rig
M-Audio Oxygen 61
Creative Sound Blaster X-Fi Elite Pro
Reason 4.0
FL Studio 8
Last edited by Cynoxx at Apr 26, 2011,
#10
Quote by TK1
sounds like the tubes are bad. check them for arcing, and replace asap.


The only useful post in this thread. EDIT: Besides Cathbard, of course.

You most likely have a power tube that failed, and took out the HT fuse. The most logical step at this point would be to have a technician evaluate the amp for damage to the power supply or grid resistors before installing new valves.

EDIT: It sounds like you may have either shorted the tube socket and/or blown open the grid resistor.
Tastes like chicken, if chicken was a candy.
Last edited by ConfederateAxe at Apr 26, 2011,
#11
OK, sounds like a dodgey valve took out the screen resistor. Replace the resistor first, check all the wiring associated with that resistor for melted insulation, then replace the tubes and test it - in that order.
Remember to discharge the filter caps before sticking your fingers in there. If you don't know how to do that keep your mits out of there.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#12
Quote by Cathbard
OK, sounds like a dodgey valve took out the screen resistor. Replace the resistor first, check all the wiring associated with that resistor for melted insulation, then replace the tubes and test it - in that order.
Remember to discharge the filter caps before sticking your fingers in there. If you don't know how to do that keep your mits out of there.


Is there a risk of death?

Picture (HUGE):
http://i.imgur.com/NWqyf.jpg">Picture Link
Guitar rig
Schecter C-1 Classic
Boss GT-8
Mesa 50/50 Power Amp
Avatar G212H 2x12 Cab

Synth Rig
M-Audio Oxygen 61
Creative Sound Blaster X-Fi Elite Pro
Reason 4.0
FL Studio 8
Last edited by Cynoxx at Apr 26, 2011,
#13
YES

don't touch anything in there if you don't know what you are doing. just don't. just go ahead and take it to a tech. ask if he could guide you through the process and show you what he is doing. that will help you learn more than sending lethal amounts of electricity through your body.
Originally posted by primusfan
When you crank up the gain to 10 and switch to the lead channel, it actually sounds like you are unjustifiably bombing an innocent foreign land.


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#14
Don't **** with those capacitors man. Like they say people get seriously hurt/die.

I got hit with a TV cable power chord a friend threw over a TV as we were moving. Knocked me flat on my ass and burned my chest through my shirt.
#15
Hell yeah! Built in stage effects! That way the audience knows you are legit! Rock it!
#16
Oh, **** son. Do not touch those caps with your fingers. Take it to a tech if you can't do exactly what cath is saying.

Pretty much, unless you know exactly what the frack you're doing, do not touch.
Gear-Ibanex rg7321 w/dimarzio pups--->Ernie Ball Jr. Vol pedal--->TS9-->Line 6 DL4--->ADA MP-1--->Marshall 9005 poweramp--->Line6 4X12 straight cab w/v30s
#17
Those orange drops won't kill him. It's the filtering he needs to worry about.
Everyone is entitled to an opinion.

Feel free to express yours so I can make an informed judgement about how stupid you are.
#18
Quote by Cynoxx
Yo dudes,
First, here's my setup:
Guitar -> Boss GT-8 (preamp) -> Mesa 50/50 (power amp *BROKEN*) -> Speakers (2x12 8ohm)
How do I fix this without having to bring it to the amp repair shop?

find a tech that makes house calls.