I've tinkered with the Ampex 600 series; not familiar with the 122. But I'd assume you're finding a general contact cement that's solidified over the years. You might try a few drops of acetone or isopropyl alcohol to soften it, or you might find that you can simply peel it free with your thumb nail or a semi-dull straight edge screwdriver. Then again, have you tried to break the screws free nonetheless? You shouldn't damage anything using conventional tools/methods. That stuff's nothing more than primative 'loctite'. Now, the rubber bushings that the motor rests on?? They're probably toast