fossil, this is how to dismantle it "Remove the screws from the back cover. Remove the cover. The power wires are plugged in place on mine. Remember where they go, one black, one white and one green. They MUST go back where they came from. If the green is soldered in place, and some are, unsolder it for removal. Disconnect the reverb and the speaker wires making sure you note the location of these wires. Polarity is important. On the sides of the amp and forward remove the 2 screws that are about 8 inches up. One on each side and probably black in colour. Now from the inside, there are 2 screws that hold the speaker wooden frame to the lower part of the amp. Remove these. Now, from the back push the speaker and wooden frame towards the front and it will pivot forward top first. Lift the speaker out of the front of the amp. Now, remover the screws holding the handle in place. These hold the amp chassis in place so keep a hand under the chassis to catch it. Once free remove it through the front opening. Now we move to the chassis. Remove all of the knobs and nuts under the knobs holding the switches to the chassis. Remove the screw at the AUX input. Remove the nuts at the input and headphones jack. Unplug the 4 wires at the power switch and make sure that you mark where they go. This is important. They must return to the same pins when reinstalled. Unplug the yellow and red wires and plug from the transformer at the chassis. There may be a tywrap on the speaker wires to this transformer wiring. Clip it. Now, flip the chassis over and remove the 2 screws that hold the heat sink/chassis mount to the main chassis frame. The PCB board should now be free of the metal chassis. Unsolder the headphone jack. Looks like 8 or 9 solder joints. Go slowly and move the jack a little at a time until it is totally removed. Now reinstall the new jack and reassemble in reverse order." source. Also, remember that there was an updated service manual due to the fact that some of the IC's were no longer in production. Hope that is not the one you will need. Hope this helps, good luck.