Amplifier Trouble

[El Dunco]

I have a 25 watt 1x120tube combo . My Dad played harmonica through it while it was connected to another speaker (so it was running 2 8ohm speakers)

Since then it has stopped working. It powers up (the light comes on) but produces no sound. I checked to see if there were any loose tunes which there weren't, then I checked to see if the soldering had come undone (I changed speakers a while back) and failing that I changed the speaker.

It still doesn't work.

I tried a different set of preamp tubes as well.

Could it be a power tube or transformer problem?

 

[Low_fidelity2100]

Re: Amplifier Trouble

Check the Fuses?
Some amps have only one Mains fuse. While others have Multipule fuses through out the circut. If it has multipul fuses, One may have blown. And it may be in a spot where the amp still powers up, and the pilot light lights, and the tubes still glow, etc... But It may be cutting signal to the speaker.

So look closely, and try and find Every fuse in the circut. Check em all. Even if they Look fine, Check em with a meter just to be safe. Set it to the 20k Ohms setting. If ya get no reading, then its blown an you need to replace it. If you get a Reading of 0k Ohms, Then the fuse has continuity, and its not blown.
If you do find a blown fuse, replace it with the SAME EXACT kind. If ya can't find the same exact kind, either order them online and wait for them. Or don't replace the fuse at all. haha.
If it keeps blowing fuses, then theres something else wrong (it wouldn't have blown a fuse for no reason in the first place). An you'll need to take it to a tech, or fix it yourself if you can actually figure out whats wrong with it. Even if ya do know whats wrong with it, If you can afford it, I'de still recommend takeing it to a tech.
The ONLY reason I always try to fix my own gear is cause I'm too poor to pay someone else to do it (and I can assure you even with being poor and attempting to figure stuff out myself, I almost always endup takeing stuff to a tech anyways). So if you can afford it, or can talk someone else into paying for it, Then Your best off leaving the work to professional.

 

[El Dunco]

Re: Amplifier Trouble

Check the Fuses?
Some amps have only one Mains fuse. While others have Multipule fuses through out the circut. If it has multipul fuses, One may have blown. And it may be in a spot where the amp still powers up, and the pilot light lights, and the tubes still glow, etc... But It may be cutting signal to the speaker.

So look closely, and try and find Every fuse in the circut. Check em all. Even if they Look fine, Check em with a meter just to be safe. Set it to the 20k Ohms setting. If ya get no reading, then its blown an you need to replace it. If you get a Reading of 0k Ohms, Then the fuse has continuity, and its not blown.
If you do find a blown fuse, replace it with the SAME EXACT kind. If ya can't find the same exact kind, either order them online and wait for them. Or don't replace the fuse at all. haha.
If it keeps blowing fuses, then theres something else wrong (it wouldn't have blown a fuse for no reason in the first place). An you'll need to take it to a tech, or fix it yourself if you can actually figure out whats wrong with it. Even if ya do know whats wrong with it, If you can afford it, I'de still recommend takeing it to a tech.
The ONLY reason I always try to fix my own gear is cause I'm too poor to pay someone else to do it (and I can assure you even with being poor and attempting to figure stuff out myself, I almost always endup takeing stuff to a tech anyways). So if you can afford it, or can talk someone else into paying for it, Then Your best off leaving the work to professional.

It only has one main fuse.

I appreciate the help though. Any other ideas?

 

[Low_fidelity2100]

Re: Amplifier Trouble

Does it make Any sound at all? Hum? Hiss? anything?

 

[kmcguitars]

Re: Amplifier Trouble

1st thing to check is are ALL the tubes glowing? I you where runnig a 2nd 8 ohm load? This means the amp was running a 4 ohms. Running a 8 ohm amp at 4ohms will stress the amps componets. So lets hope it's not a X-former.
If you could tell what make and model amp it is would be helpful.

 

[El Dunco]

Re: Amplifier Trouble

It doesn't hum, hiss or make any sound whatsoever. It can't be a transformer because the power lights turn on and It is a Johnson Loredo.

It was also designed to run 2 speakers at 4 ohms.

The power tubes are glowing

 

[El Dunco]

Re: Amplifier Trouble

bump

 

[wixedmords]

Re: Amplifier Trouble

Beer, are all the preamp tubes glowing?

There are usually fuses inside the chassis. Remember with fuses they can look good and still be bad, so either check them with a multimeter or replace them. Then check to see if anything looks burned inside the chassis. After that you could try to plug the amp into a known good cab.

 

[El Dunco]

Re: Amplifier Trouble

it was the dammed OT!