Bugera G5 Infinium Enigma

scozz

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I have a Bugera G5 Infinium, I’ve had it about 5 or 6 years and it’s been great.

I haven’t used it very much the last two years, and it’s developed a problem, and the problem seems weird to me…

There’s no sound coming from the speaker,… the headphone jack and the line out jack work fine, but no sound from the speaker.

?

Should I try bridging the loop to see if there’s sound?

Anyone have this happen with an amp?

Thanks.
 

South Park

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Yes you can bridge the FX loop and plug into the return and play the power section . You may have a bad connection on the jacks . Check the fuses to
 

scozz

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Maybe the output tube took a shit.
That’s the first thing I thought about, the tubes. But I haven’t checked anything yet, including the tubes. Mostly because I can’t wrap my head around how is it that I can play through my headphones, in the e-out jack, and it sounds perfect,… but complete silence coming from the speaker?!
 

scozz

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Yes you can bridge the FX loop and plug into the return and play the power section . You may have a bad connection on the jacks . Check the fuses to
Thanks for the suggestion SP, I appreciate it. I tried it and no luck, complete silence.

Have you seen this before,… where a speaker, (that works fine, and a speaker cable that works fine), is completely silent and I can play through the headphones, in the e-out jack, and it sounds perfect?! :hmm:

I just don’t understand how that’s possible, what am I missing? :shrug:
 

South Park

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Your problem is in the power tube section if the head phones work it is the preamp section . It is going to be tubes or transformer you can try different tubes . With power on and tubes in with no guitar you will get some noice his pops anything means the transformer is working
Thanks for the suggestion SP, I appreciate it. I tried it and no luck, complete silence.

Have you seen this before,… where a speaker, (that works fine, and a speaker cable that works fine), is completely silent and I can play through the headphones, in the e-out jack, and it sounds perfect?! :hmm:

I just don’t understand how that’s possible, what am I missing? :shrug:
 

scozz

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Your problem is in the power tube section if the head phones work it is the preamp section . It is going to be tubes or transformer you can try different tubes . With power on and tubes in with no guitar you will get some noice his pops anything means the transformer is working
Sorry but I’m not really clear what you mean in your first sentence. The way it reads I’m not sure if you’re saying my problem is more likely the tubes or the transformer?

Just to clarify,…. you’re suggesting it could be a tube if I hear noise, crackling or hiss,….

And if it’s the transformer it would be dead silent,…

Then it’s the transformer then, because I’m getting no sound of any kind, dead silence.

I have spare power and preamp tubes so I’ll try a new power tube, there’s only one in this amp and only one preamp tube also.

Thanks again for the help! :yesway:
 

South Park

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Sorry about the replay if you get any noice at all even the smallest amount the power tubes and transformer is working . The two main things that can go bad are tubes and transformer if one or the ether is bad you get no noice . You can check the bias voltage if the bias is bad all you will hear is the heaters . When you build amps this is how you test the power section
 

scozz

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I don't have this amp, and I'm far from some sort of diagnostic expert, but I didn't see a replay about fuses.
I missed that fitz, thanks for reminding me, yes the fuse is fine.

Tomorrow I’m going to replace both the power and preamp tubes, as I mentioned before there’s only one of each.

The preamp is your regular 12AX7, but the power tube is a 12BH7. Now that I think about it, l don’t know if I have a spare 12BH7.
:hmm:
 

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