5150 Issue...

J

JRSOLDJA

New member
My new 5150 III 50watt head came in yesterday....with no sound output...not even white noise or static.

This was an "open box" item I bought off of MF. I checked the power tubes...they're lighting up just find, all preamp tubes look fine EXCEPT...the V9 position 12AX7 tube. It has a ton of white powder residue under the glass surface...looks like Frosty the snowman blew a load in it. Also...something interesting to mention...the tubes are not labeled. This is suppose to be a new head with JJ's. But I've never seen them unlabeled before. Could the last person that had it taken out the new JJ's and put some old crap ones in or something before sending it back...? any thoughts here are appreciated. Thank you!

- J.R.
 
Re: 5150 Issue...

Looks like your amp's phase inverter tube lost vacuum. Replace it and see if it helps.
 
Re: 5150 Issue...

vinta9e said:
Looks like your amp's phase inverter tube lost vacuum. Replace it and see if it helps.
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Yea, thats what I'm hoping it is and nothing else. What causes a tube to just lose vacuum by itself? Thanks guys. MF is sending me a free replacement tube. But what about the fact that all of these tubes are unlabeled while they are suppose to be JJ tubes....?
 
Re: 5150 Issue...

Awesome! :banghead: you would think that MF would check that once they got it back lol....unbelievable
 
Re: 5150 Issue...

JRSOLDJA said:
Awesome! :banghead: you would think that MF would check that once they got it back lol....unbelievable
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Being its an open box item who knows what actually happened... Could have even been that MF got the amp back cause of a tube problem and swapped them themselves.
 
Re: 5150 Issue...

I wouldn't keep used tubes in a used amp for long anyways so the non-labeled tubes would be a moot point to me.

Start with replacing the bad tube and see if it helps first. Then I'd suggest a good retube anyways.
 
Re: 5150 Issue...

Edgecrusher said:
Being its an open box item who knows what actually happened... Could have even been that MF got the amp back cause of a tube problem and swapped them themselves.
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Yea, thats a good point. They did say it was returned in perfect condition though...apparently that statement doesnt have anything to do with the tubes haha.
 
Re: 5150 Issue...

Surgeon said:
I wouldn't keep used tubes in a used amp for long anyways so the non-labeled tubes would be a moot point to me.

Start with replacing the bad tube and see if it helps first. Then I'd suggest a good retube anyways.
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for sure...one reason I've always been hesitant on buying used tube amps, but it was brand new and returned within 30 days....so I figured maybe it wouldnt really be like buying a "used" one...ya know...? lol. I should've just bought one brand new....smh
 
Re: 5150 Issue...

Well, if the price was right why not go used, always better prices IMO and, as I said, if it's only a tube-related problem it's really not a big deal.

Fix it up and rock that thang!
 
Re: 5150 Issue...

If you've got another amp with a 12AX7, just pull one from there and pop it in the 5150III to see if that works.

Getter flash should be silver. It turns white when exposed to air.
 
Re: 5150 Issue...

crguti said:
You must connect the head to a cab to get sound

:dunce:
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Haha! Thanks crguti...you're infinite wisdom is inspiring. I guess I should've mentioned when I PLUGGED it into a CAB and connected my guitar with all the volume controls up and blah blah blah..no noise lol!
 
Re: 5150 Issue...

GilmourD said:
If you've got another amp with a 12AX7, just pull one from there and pop it in the 5150III to see if that works.

Getter flash should be silver. It turns white when exposed to air.
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yea, unfortunatly my other head is back home a few states away. But MF is sending me a new JJ 12ax7. I just feel its weird that none of these tubes are labeled also..
 
Re: 5150 Issue...

allbutromeo said:
The main question is, would re-tubing it be cheaper than returning it and buying a new one?
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Thats exactly why this is bothering me so much...I could've gotten a brand new one for like $100 more. And I'm sure you know as well as I do that retubing a 5150 III and having it biased is waaay more than $100. If the new 12ax7 doesnt fix the problem and if it doesnt sound like it should at all then I'll definately send it back and just get the brand new one...
 
Re: 5150 Issue...

Surgeon said:
Well, if the price was right why not go used, always better prices IMO and, as I said, if it's only a tube-related problem it's really not a big deal.

Fix it up and rock that thang!
Click to expand...

Exactly, tubes are expendable.

And if the OP is like me, he'll end up with his own tube cocktail in there anyway.
 
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