#1
Right, I was playing my amp and then suddenly the sound cut out came back for about 2 secs then went out again and now won't make any noise and the tubes aren't glowing. It's a Laney VC15.

I play straight guitar to amp no effects so that rules that out.
I thought it was the cable so plugged into another amp and it works fine so it's not that.
Therefore it's with the amp.

I don't know whats wrong or how to test anything. Please help
Quote by saphrax
Bit harsh I think! He comes back for the last 10 minutes against Roma, after being out all season, and you want him crippled again? You harsh wanker!


Aimed at me for saying I hope Gary Neville breaks all his limbs
#2
sounds like a bad tube, and it may have blown the HT fuse if it has one. Does it have a mains and HT fuse?
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#3
HT fuse being the 100mA one in the back of the amp? How do I know if it's blown or not? I thought it could be the tubes... How would I go about replacing them or finding out which one it is? Also how much is it gonna cost to fix if it is the tube. I thought tubes would last longer than half a year (got the amp early Jan and havn't played it that much what with GCSE's).
Quote by saphrax
Bit harsh I think! He comes back for the last 10 minutes against Roma, after being out all season, and you want him crippled again? You harsh wanker!


Aimed at me for saying I hope Gary Neville breaks all his limbs
#4
Take is to a professional, it's not good to go poking around the back of tube amps if you don't know exactly what you're doing
ohai little sig.
#5
Quote by Azza Dutt
HT fuse being the 100mA one in the back of the amp? How do I know if it's blown or not? I thought it could be the tubes... How would I go about replacing them or finding out which one it is? Also how much is it gonna cost to fix if it is the tube. I thought tubes would last longer than half a year (got the amp early Jan and havn't played it that much what with GCSE's).

is the amp powering on, like indicator comes on, but the tubes aren't lighting up? I'm not familiar with your amp, but are there 2 fuses, one for the mains, and a seperate one? It's pretty easy to check the fuses, but it might be hard to see if they are actually cooked. If you have 2 fuses, and the amp actually powers on, but the tubes don't light up, that would be a strong indicator that the HT is popped.

Tubes can go at any time man, it's an ancient technology by todays standards, and they aren't made to the standards they were when they were in wide use. It's easy to replace them, they go in straight on pins, no twisting. The hard part is biasing them correctly, since you usually have to access a bias pot inside. Depends if it's fixed non adjustable bias too. Power tubes are usually around $10-20 USD a piece for standard variety, not sure how much a tech will charge to bias it for you, but it shouldn't be too much.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Jul 18, 2008,
#6
Quote by Erock503
is the amp powering on, like indicator comes on, but the tubes aren't lighting up? I'm not familiar with your amp, but are there 2 fuses, one for the mains, and a seperate one? It's pretty easy to check the fuses, but it might be hard to see if they are actually cooked. If you have 2 fuses, and the amp actually powers on, but the tubes don't light up, that would be a strong indicator that the HT is popped.


Yea the LED's come on but the tubes don't. How can I check the fuse?
Quote by saphrax
Bit harsh I think! He comes back for the last 10 minutes against Roma, after being out all season, and you want him crippled again? You harsh wanker!


Aimed at me for saying I hope Gary Neville breaks all his limbs
#7
Quote by Azza Dutt
Yea the LED's come on but the tubes don't. How can I check the fuse?

well, with the amp unplugged, take out the fuse and examine it. If it's the clear glass kind, you can usually see the filament running thru the middle. If that's not continuous, it's popped. Sometimes it will be broken at the end though, so you won't see it with the metal covers on each end.

If it is popped though, there was a reason. It's meant to safeguard the rest of the amp if there is a tube problem or some other problem. My first guess would be a bad powertube, so I wouldn't "just" replace the fuse.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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