My Mark III died...

[rgx612a]

Was playing at a decent volume for about 15 mins and all of a sudden it had a huge volume drop...the amp is extremely weak now... there's next to no volume in any of the channels, just a really weak signal. I changed the power tubes and pre-amp tubes, tried a patch cable through the effects loop.

I didn't smell any burning or anything and i checked inside and nothing looks blown on it??

Is there anything i should check before i try to find a tech to look at it?

 

[acorkos]

you can determine if the problem is in the preamp or power amp....it'll help in your troubleshooting. plug your guitar straight into the effects return jack. any sound? it won't be as loud as the normal amp sound, but if no sound, the problem's probably in the power amp. plug your guitar into the main input jack, with a second guitar cord running from the effects send jack into another amp. if the preamp is ok, all the front panel controls should still work.

 

[rgx612a]

I tried that. The power amp seems to be working, so it's something in the pre-amp.

 

[acorkos]

even though you swapped tubes, there's a 95% chance your problem is tube related.

i would flip your amp upside down, remove the tube shields, and one at a time, rock each tube in its socket while pushing it into the socket, making sure you have good solid contact. if that doesn't help, i would next try spray cleaner and a pointed probe to clean and tighten each element of each tube socket. remove each tube, spray on some cleaner, insert/remove/reinsert/re-remove each tube and then tighten the elements. reinsert each tube and cross your fingers. I'm betting that will solve your problem....good luck

 

[rgx612a]

How much do you think Mesa would charge to repair this thing?

 

[rgx612a]

so i had the amp shipped out to Mesa yesterday. the guy i was talking to (Rich) said around $150 - 200 for the repair and a check up to make sure everything else is working good.

now that it's on it's way to mesa i've thinking about that iic+ mod...keep in mind i'm pretty **** happy with the way it was sounding before... but i'm curious. also thinking about getting it re-capped... what kinda money to get this stuff done?

 

[stokes]

Cap job shouldnt take an hour on that amp.It would be very beneficial in an amp that old.Could very well be the cause of your symptoms.

 

[stokes]

Yeah,I dont know whats up with Mesa,they say that a lot.They use Illinois caps for the mains,not the best by a long shot.

 

[Restless Rocks]

Mesa will probably replace your FX loop jacks and clean the tube sockets and pots. And unless you specifically request replaceing all your filter caps they will test and determine which, if any, of the caps need replacing. The iic+ mod will not make your mark III sound like a IIC+ but will smooth some of the aggresivness that some folks really like about the MkIII especially the lead channel. The RI will be a bit more sibilent (for lack of a better word) accentuating the upper highs (presence) in a slightly different way. These changes are subtle and far from a dramatic (like getting another amp) difference but IMHO are very very nice.

 

[rgx612a]

OK, i think i'll pass on the c+ mod. I'm happy with the way it sounds as it is.

It's a Red Stripe simul-class head so it's got some fairly smooth lead tones in there when i need them (presence low), but i'm more of rhythm guy, so i like a little more grind in my tone. the C+ mod might make it too smooth for me??

A cap job is a serious consideration though, so i'm going ask about that the next time i talk to one of the guys at Mesa. I guess they'll give me a call once they diagnose the problem...