Hi Phatt
Thanks for the tips!
I found the points you listed on the PCB however I have never done this type of troubleshooting before so I have a few basic/stupid questions:
-What do you mean by "either side of common"? I can't find a GNDA label on the PCB (I might just not have looked hard enough   xP ) Im guessing GNDA is a ground and that I should measure the voltage between the TPx points and ground?

-When I do these measures should the amp be powered or shut off?

again thanks everyone for all the great input!

Update:
I have, at long last, gotten around to re-solder the whole board. Next up is checking all the cables for damage. Is changing the thermal putty-thingy for the transistors mounted on the heat sink important?

Ok so here is a picture of the thermistor labled "RT1" (in the center, covered with white stuff). Its not mounted against the heat sink, but placed right next to it. That was just my bad English running loose

I dont know how to crop it for this topic, but Ill supply a link to it instead: http://i.imgur.com/GYK4g.jpg

I have removed the board from the housing and looked over the soldering. The soldering looks very good, though I will go over it with my soldering iron to make sure. Also I will check for contact between the various connected nodes.

Great!
Ill do this and upload pictures as soon as I can find the time. Thanks a lot for your input! I'm hopeful for this project!

10 points to you Roly!!
The amp was put together in 1999. Would breaking down in 2012 be considered long durability? I really don't know as this is the first amp I have ever owned apart from a Roland MicroCube

Ok so I've checked the speaker and the PCB and both look alright apart from the thermistor which is covered in a white substance. This might just be isolation but I thought it might be worth a mention. Any suggestions on what to do next?

Hm yes Ill try that and get back to you. Thanks for the input

Hi all! My first post!
I have a Princeton 65' guitar amp which I have always treated with care. The other day however when I turned it on the signal (playing through the clean channel) was distorted and lacking of any treble response. The distortion sounds a bit like the effect from a dist. pedal however when the notes decays they all end in a fart-like crackling sound.
I have no idea how I came to harm the amp. Does any of these symptoms sounds familiar to anyone?/Any suggestions? I'm planning to change the fuse and unscrew the speaker to check if it is torn in any way. I have found the schematic, but cant make a lot of sense out of it.

any response is highly appreciated!  <3)