I recently bought a 77 Guild S300-D that is all original. The only problem with this lost classic is that it tends to go out of tune very frequently. Some strings make that ‘ping’ sound during tuning so I guess the nut is part of the problem. I was wondering if anyone had any suggestions about what to do about it. Im not too worried about decreasing its value so Ive been thinking about replacing the nut, adding locking tuners, or both. Please email me with any insights or suggestions. Thanks. -Ben Dewar