#1
I'm kind of freaking out here so I'll spare you the pleasantries:

My Marshall JCM2000 DSL401 combo tube amplifier is not working for some reason. Here's exactly what i've done with it in the past 24 hours

Last night, I get home, let it warm up for about 20 minutes and then practice for about 2 1/2 hours, it works fine, no problems with tone, no problems with static, nothing is out of the ordinary at all.
Today, I get home early from school, turn it on standby for about 2 hours while I do homework, now my amp is right next to my desk so I noticed that it was humming slightly more noticeably than usual, but thought nothing of it. I finish my homework, turn the amp on... nothing.

-I checked all my cables, they were all fine, then I just bypassed my effects chain and plugged straight into the amp, at this point I noticed that there was absolutely NO signal coming out of the amp, even when touching the tip of the cable with my finger.

-All status indicators are lighting up properly, the on/off indicator works, there is no static coming from the amp, but rather a fairly quiet, mild hum.

-This amp was last serviced about 15 months ago at a very reputable professional guitar/amp repair shop (ProTech Audio, if anyone knows the place). The primary reason I took it by was because the audio would flicker in and out and sometimes the amp wouldn't work at all.

When I got it serviced they replaced all the tubes, and also resoldered all the connections within the amp because apparently they had cracked and failed over time.

-I bought this amp used, so I'm not really sure how old it is, but it's certainly in very nice condition (or used to be, at least)

-I usually set the amp's master volume from 2-4, then use a clean overdrive to compensate. The loudest it's ever been for extended periods of time is 8-9 when my friend and I practice together (which we haven't since late august)

-I use this amp regularly, the longest it sat unused was perhaps 1 1/2 weeks when my family went on vacation over the summer. I would say that on average, I use it anywhere from 1-3 hours a day, give or take.

-There have been no recent power surges or anything that I know of, I also doubt that someone knocked it off it's stand or something like that as I closely inspected it for visible damage.

-Most importantly, the tubes do not light up at all. The amp is cold as a rock.

Any help at all is highly appreciated. I ****ing love this amp but if I have to drive 2 hours out of my way and spend another $220 to get it repaired that's going to be a major problem.
#2
Get new tubes.
Quote by aldo47
(i thought hot strings would make me finger faster.)
so i tried to set my strings on fire by putting a lighter on the high e string n it cut it so wtf??!!? i passed the lighter rrly slowly by it for less then a sec n then it snapped...
#4
Quote by Schism1985
Seriously? Even though I just replaced them less than 2 years ago?


Could be.

With heavy use and a hot bias, tubes last about a year.

But that amp (IIRC) runs el84's; I've never seen an el84 amp do that.
Not that it's impossible, but they tend to be more stable than Marshall's running el34s.

Also, your amp has TWO fuses, it sounds like the HT fuse, not the Mains fuse is blown.

It's usually a tube failing that pops this one.
#6
Quote by Schism1985
fffffuucckkkk

So... new tubes? how much does that usually cost? Last time I got tubes+the other repairs and they didn't tell me how much they both cost separately...


If none of your tubes are glowing then you have a problem. Sounds like a tube went down the drain and took a fuse or something else with it. I wouldn't just rush out and buy a set of tubes until you can find whats killing the power.
#7
okay I just have to ask, I know you'vfe probably checked this but just in case you haven't, is the power cable lose? I've done it before, freaked out for like 2 minutes before I realied my power cable fell out the back.
no sir away a papaya war is on
#8
I think his power and channel lights are on, so power cord or mains fuse won't be it.

A new fuse is about $3 for a 4 pack, no worries there.

A matched quartet is only 60-70 bucks:
http://www.parts-express.com/wizards/searchResults.cfm?srchExt=FILTER&searchFilter=el84%20quartet&CFID=1500371&CFTOKEN=73166356

That, my friend, is getting off EASY in the world of tube repair...

As much s#!t as DSL's get for their reliability, the 401's are pretty solid.
Never run into much more than (surprise!) a bad tube taking out the HT fuse.

No tech work needed here, you can pop these in yourself.

If you're lucky, maybe just the fuse popped for no good reason, it happens.
#10
If its a fixed bias chassis, then no. Pop old tubes out, put matched new ones in, make sure the pins are seated correctly.

Have both the fuses been checked? I understand it sounds redundent, but its good to check.
1981 Gibson Les Paul Custom (Black Beauty)
1980 Marshall JMP 2204
#12
Quote by Schism1985
How do you check the fuses?


Unscrew number 8, labelled HT fuse on your back panel.



Use a dime or something.

When it pops out, remove it from the black plastic holder you just unscrewed.
Look at the glass part of the tube, and the element inside it.
If you see ANY discoloration, usually brown or black, on the glass or element, or any sign of damage to the element, like lumpy or bent spots, the fuse is toast. Bring it with you to radioshack and have them match it.

Put the new one back in the holder, doesn't matter which way, and scerw it back in snug.

See if it's fixed.

If not, check the fuse again.
If it blows it again, you've got a bad power tube.
#14
Quote by Schism1985
**** i don't think the fuse looks like it's damaged. The inside of the glass looks foggy tho, could that mean anything?


Hrmmm...

that doesn't sound blown to me.


Well, I'd still at least try it before taking it in...

Fuses are only a buck or two, and it's never a bad idea to have some spares.