amp techs, give me the bad news

Al.C

New member
Okay guys my first problem with a Boogie in 25 yrs. Two weeks ago I received my new Lonestar Special head(I know I have not posted photos/clips/review yet but still gelling with it ). Was playing yesterday at home and it just suddenly died, no pop/distortion/noise/hiss just dead instantly . Checked the fuse,blown. Unfortunetely I had no 2A slo blo fuses on hand (and they no longer put a spare inside the cab), and I am smart enough not to put in any of the 3A fuses I do have so I waited until today so I could get a pack of fuses. First simply replaced the fuse, maybe simply a bum fuse. Blew as soon as the power switch was thrown (still on standby). Replaced all the power tubes (EL84's), new fuse, same result. Replaced all pre-amp tubes as well , switched to 30 watt setting which uses silicon diodes rather than the 5Y3 rectifier,same result. Pulled the 5y3, kept it on the 30 watt setting and once again instant blown fuse.
I sent an e-mail to Mesa Hollywood (were I purchased the amp) so I can send it in for repair but this has me curious. In the last 35 years of playing I have never had an problem that couldn't be fixed by a fuse or tube replacement. Educated guesses welcome.
 
Re: amp techs, give me the bad news

Don't worry about it, man. The Boogie shop should take care of you! They sold it to you like that, right? So I am assuming they will take care of it free of charge.

I am no electronics whiz, but the fact that a fuse blows instantly no matter what would bring to mind the possibility of an easy-to-find short to ground somewhere not too deep in the circuit. It should be easy for them to find an fix.
 
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Re: amp techs, give me the bad news

A diagnosis is not readily made, without being able to actually look at the amp. Have you turned it on with all the tubes removed? If it still blows then, it is likely in the power supply area.
 
Re: amp techs, give me the bad news

Don't worry about it, man. The Boogie shop should take care of you! They sold it to you like that, right? So I am assuming they will take care of it free of charge.

I am no electronics whiz, but the fact that a fuse blows instantly no matter what would bring to mind the possibility of an easy-to-find short to ground somewhere not too deep in the circuit. It should be easy for them to find an fix.

Not worried, just curious. Boogie has a great customer care reputation and the amp is only 2 1/2 weeks old. Just the way it went out. Worked perfectly then instant death without even a whimper. My guess is a poever section short as well but don't know what would fail suddenly up there.
 
Re: amp techs, give me the bad news

A diagnosis is not readily made, without being able to actually look at the amp. Have you turned it on with all the tubes removed? If it still blows then, it is likely in the power supply area.


unfortunately ran out of the 4 pack of fuses i bought so unable to fire it up without tubes, never thought of that, actually never ever did that on any amp. Would the pilot lights even light up?
 
Re: amp techs, give me the bad news

unfortunately ran out of the 4 pack of fuses i bought so unable to fire it up without tubes, never thought of that, actually never ever did that on any amp. Would the pilot lights even light up?

They should, if the fuse holds out. If not, then no. At this point it's just curiosity to check, so don't worry if you don't want to spend the coin on fuses.
 
Re: amp techs, give me the bad news

I'm no expert but when my Marshall did the same thing, I was told new fuses wouldn't work becuz the transformer was bad.

Tubes ok. Fuses ok. Transformer bad?
 
Re: amp techs, give me the bad news

Answer was: One of the 1n4007
diodes in the high voltage rectifier circuit went bad..

A $0.01 part. Mesa was great, had UPS pick amp up at my house. Only 24 hr turnaround on diagnosis and repair. Amp will be back Wednesday
 
Re: amp techs, give me the bad news

Answer was: One of the 1n4007
diodes in the high voltage rectifier circuit went bad..

A $0.01 part. Mesa was great, had UPS pick amp up at my house. Only 24 hr turnaround on diagnosis and repair. Amp will be back Wednesday

Also being a Boogie owner this is great news!
 
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