SF Princeton Reverb. Help!

BootRoots · May 15th, 2007, 10:20 AM

So I was playing my SF 68 Princeton Reverb the other day and the volume started swelling for no reason. Kinda faded in and out, and then....just out. Now when I turn the amp on there is a humming sound that fades out after about 3-4 seconds. There also seems to besome kind of buzz or rattle comming from some where near the rectifier tube. I get absolutly nothing when I plug it in though.

Needless to say I will be taking it back to the tech to have him answer some questions about his work (i just had it in there to be looked at and he replaced the power tubes and say everything looked okay), but I was wondering if anyone here might be able to help out. Does this sound like a tube thing? help.

Thanks

dibber124 · May 15th, 2007, 10:28 AM

Quote:

Originally Posted by BootRoots

So I was playing my SF 68 Princeton Reverb the other day and the volume started swelling for no reason. Kinda faded in and out, and then....just out. Now when I turn the amp on there is a humming sound that fades out after about 3-4 seconds. There also seems to besome kind of buzz or rattle comming from some where near the rectifier tube. I get absolutly nothing when I plug it in though.

Needless to say I will be taking it back to the tech to have him answer some questions about his work (i just had it in there to be looked at and he replaced the power tubes and say everything looked okay), but I was wondering if anyone here might be able to help out. Does this sound like a tube thing? help.

Thanks

Suggest that you have the condition of the filter caps checked.

Jef · May 15th, 2007, 02:46 PM

In a princeton reverb, the filter caps are in one can cap, behind the power tubes. Those are a pain to remove (sometimes soldered to the chassis) and you probably won't find a replacement of the same values and size. never saw one of those can caps go wrong, however. Looks like they are more durable than the 'normal' axial electrolytic caps.

does the pilot light come on?

Jef

BootRoots · May 15th, 2007, 02:55 PM

Quote:

Originally Posted by Jef

In a princeton reverb, the filter caps are in one can cap, behind the power tubes. Those are a pain to remove (sometimes soldered to the chassis) and you probably won't find a replacement of the same values and size. never saw one of those can caps go wrong, however. Looks like they are more durable than the 'normal' axial electrolytic caps.

does the pilot light come on?

Jef

yes the pilot light comes on.

PhatTele · May 15th, 2007, 08:56 PM

It sounds like "a tube thing" to me.

Meanwhile, Antique Electronic Supply sell direct replacements for those cap cans (see link)

http://www.tubesandmore.com/scripts/...m=C-EC20X4-475

BootRoots · May 16th, 2007, 09:51 AM

Quote:

Originally Posted by PhatTele

It sounds like "a tube thing" to me.

Meanwhile, Antique Electronic Supply sell direct replacements for those cap cans (see link)

http://www.tubesandmore.com/scripts/...m=C-EC20X4-475

thanks for the heads up. I'm gonna swapp the tubes and see what happens. after that its off to the tech.

145Guy · May 16th, 2007, 11:26 AM

Make sure you check the Rectifier tube also, and don't be too hard on your tech. it's impossible to diagnose problems that havn't occured yet.

BootRoots · May 16th, 2007, 02:32 PM

Quote:

Originally Posted by 145Guy

Make sure you check the Rectifier tube also, and don't be too hard on your tech. it's impossible to diagnose problems that havn't occured yet.

I hear ya. hes worked on several things for me in the past and always done right by me, so I will give him the benifit of the doubt.

Tim Swartz · May 16th, 2007, 03:17 PM

Quote:

Originally Posted by 145Guy

Make sure you check the Rectifier tube also, and don't be too hard on your tech. it's impossible to diagnose problems that havn't occured yet.

Yep, swap in a rectifier.

May 15th, 2007, 10:20 AM	#1 (permalink)
BootRoots Tele-Meister Join Date: Jan 2004 Posts: 309	SF Princeton Reverb. Help! So I was playing my SF 68 Princeton Reverb the other day and the volume started swelling for no reason. Kinda faded in and out, and then....just out. Now when I turn the amp on there is a humming sound that fades out after about 3-4 seconds. There also seems to besome kind of buzz or rattle comming from some where near the rectifier tube. I get absolutly nothing when I plug it in though. Needless to say I will be taking it back to the tech to have him answer some questions about his work (i just had it in there to be looked at and he replaced the power tubes and say everything looked okay), but I was wondering if anyone here might be able to help out. Does this sound like a tube thing? help. Thanks

May 15th, 2007, 02:46 PM	#3 (permalink)
Jef Tele-Holic Join Date: Mar 2003 Location: Antwerp, Belgium Posts: 684 2 Photos	In a princeton reverb, the filter caps are in one can cap, behind the power tubes. Those are a pain to remove (sometimes soldered to the chassis) and you probably won't find a replacement of the same values and size. never saw one of those can caps go wrong, however. Looks like they are more durable than the 'normal' axial electrolytic caps. does the pilot light come on? Jef __________________ Amplification is not a social dinner, a literary event, a drawing or an embroidery; It cannot be done with elegance and courtesy. Amplification is an act of violence... (Mao Tse-Tube)

May 16th, 2007, 11:26 AM	#7 (permalink)
145Guy Tele-Meister Join Date: Mar 2006 Location: Way Upstate NY Posts: 122	Make sure you check the Rectifier tube also, and don't be too hard on your tech. it's impossible to diagnose problems that havn't occured yet. __________________ "Ahh...beer, the cause and the cure of all man's problems" Homer Simpson

May 15th, 2007, 08:56 PM	#5 (permalink)
PhatTele Tele-Holic Join Date: Jun 2003 Location: Richmond, VA Posts: 732	It sounds like "a tube thing" to me. Meanwhile, Antique Electronic Supply sell direct replacements for those cap cans (see link) http://www.tubesandmore.com/scripts/...m=C-EC20X4-475