63 Concert blows one power tube

[jackmac]

I've got a 63 Fender Concert that blew one of the power tubes after only a couple hours of use. Had a tech replace the tube socket, the resisters at the socket, and new power tubes. After a couple hours, same thing, started to sound really hot (good!) and saw that the tube was glowing badly and shut it down. BTW, the amp had been in an attic for about 30 years. Any help would be greatly appreciated!

 

[SatelliteAmps]

Bad bias supply, and probably needs a complete cap job after sitting in an attic for 30 years.

 

[Baloney]

It could be your Capacitor hoses or your Speaker bearings.

HAHA seriously man take it in to a tech for a check up. 30 yrs is a long time.

 

[jackmac]

Anyone know a reputable amp tech in the Richmond or Lynchburg Virginia areas?

 

[Structo]

So the tech didn't replace any of the electrolytic caps?

Not a very good tech if he at least didn't tell you that they should be replaced.

When you have it recapped (filter caps, bias cap and bypass caps) , have them also install a three prong cord, remove the death cap and take the ground switch out of circuit.
Don't let them replace any of the coupling caps unless they are super leaky and cause the pots to be scratchy.

 

[donnyjaguar]

Satellite has the most probably cause. Check also the resistor supplying the bias voltage to the Cgrid. It could be going open circuit as the amp warms up. This is a typical failure mode.

 

[jackmac]

The tech "replaced all filter capacitors and cathode bypass capacitor, installed adjustable bias pot, replaced other components as needed, cleaned controls, retubed and adjusted bias for new tubes". I moved shortly after having the work done, and now look to getting it running.
I know I need to get it to a qualified tech. Thanks for all of the advise,
John

 

[Trout]

The tech "replaced all filter capacitors and cathode bypass capacitor, installed adjustable bias pot, replaced other components as needed, cleaned controls, retubed and adjusted bias for new tubes". I moved shortly after having the work done, and now look to getting it running.
I know I need to get it to a qualified tech. Thanks for all of the advise,
John

Sounds like a leaky coupling cap,

 

[kidmandude]

so the tech didn't replace any of the electrolytic caps?

Not a very good tech if he at least didn't tell you that they should be replaced.

When you have it recapped (filter caps, bias cap and bypass caps) , have them also install a three prong cord, remove the death cap and take the ground switch out of circuit.
Don't let them replace any of the coupling caps unless they are super leaky and cause the pots to be scratchy.

+++1