Take the back panel off, and find the 4 machine screws on the bottom, the ones that don't go through the feet. Take them out, take out the tubes (at least the power tubes) and then tilt the case back and sort of wiggle it out, very carefully. It will no doubt stick near the control panel, but don't worry about it, it's just jammed in, no fasteners. It's friggin' heavy so go slow and be careful. You can sort of carefully use the transformers as handles. I don't have date labels on any of mine, but rather a rubber stamped box with build and test dates hand written in on the '71 and '72, and a hand written grease pencil date with initials on the '68. My '71 just has 2/1 hand written in the test date box only, which I assume means Feb of '71, because I have the original warranty card with a sale date of 10/71.
If you don't want to take it apart, Send me jpegs of the front and back and I can probably tell you how old it is.
Ed
