Dual Rec Problem

[ChrisTGP]

Hey. I've got a two channel Dual Rectifier solo head, and have used it at two gigs so far, where it has worked fine. At our last gig, however, I set up with a marshall 4x12 and powered up, but had the following problem: Even with the master set to FULL, the volume was way too low. Way lower than its meant to be obviously. I usually gig with the master at about 5 (if the sound guy'll let me), but here the we could hardly hear any sound at that level. I got it home and noticed one of the preamp tubes wasnt seated properly. I fixed it, and played the amp through a small speaker which i took from an old combo. The amp worked fine, with the volume being too high for bedroom levels, set to about 2 or 3. THEN, while I had been playing for about half an hour, the amp suddenly switched itself off, and now won't power up at all. If anyone has any ideas as to the problem, please help me out, I need the amp by this saturday. Cheers.

www.theguiltypleasures.tk <----Plug :wink:

 

[Platypus]

Sounds like a tube failure which caused your fuse to blow just from the sounds of it. Get your manual and look at the 'diagnosing tube problems' section and follow their instructions.. it solves 90% of problems

 

[Guitarzan]

I think your right...good call Plat!

 

[ibanez4life SZ!]

Platypus has it! You need a new fuse....probably power tubes also.

 

[ChrisTGP]

Ok cheers fellers. Is there a way of telling if a particular tube is knackered or not? And is the problem likely to be a pre-amp or power tube? And what is the name of the fuse that I need? I mean, if I were to try to find one, what do I ask for?

 

[jbird]

The fuse is a 4 amp slo-blow. They are blown when a short occurs somewhere in the amp! Either by a tube (sometimes accompanied by a visible arc inside the tube), a shorted rectifier (diode or tube), or the OT!

 

[ChrisTGP]

how easy are the fuses to get hold of? bear in mind I'm in England and there are no Mesa stockists anywhere near me.

 

[Scary Guy IRL]

I think all you needa do is find what rating the fuse is, and head down to a local Hardware store. It should be a standard fuse...

Not 100% tho.. :?

 

[Platypus]

From the Mesa manual:

FUSE: This is the A.C.’s (Alternating Current) main fuse and provides protection from outside A .C. fluctuations as well as power
tube failure damage. Should the Fuse blow, replace it with the same rating in a Slo-Blo type package. The domestic U.S. version
requires a 4 amp Slo-Blo fuse. A power tube short or failure is often the cause of a blown fuse...Follow the
cold start procedure mentioned in the ON/STANDBY switch section and watch the power tubes as you
flip the STANDBY to the ON position. If a power tube is going bad or is arcing you will see it! Flip the
STANDBY switch to Standby immediately and replace the faulty power tube and the fuse if necessary.
If you see nothing abnormal as you lift the STANDBY switch, it is possible that a power tube shorted
temporarily and blew the Fuse. If this is the case it may work again normally. To be safe, you might want
to replace just the adjacent tube or all power tubes in the “shotgun” troubleshooting tradition and save the
replaced set as spares. Spare fuses are a must for the fabled cord bag along with your spare tubes. Always
carry both for they could be worth their weight in gold someday.
PAGE 14
FUSE
CAUTION: Unplug power before
removing fuse or bolts
holding chassis
POWER FUSE
120 V~
60 Hz
4 A
4 A
SLO
BLO

You should be able to get those kind of fuses at most any hardware or electronic shop..

 

[Lespaulstandard]

^^^ What he said lol

As for tubes, if you can afford it, I'd replace them all.

 

[redmax61]

Sage advice here. And Welcome to the Boogie Board!!