Crate CA6110DG Gunnison Acoustic Guitar Amplifier "chassis parts diagram" Questions

chassis, or pull a part number off the original speaker to match speaker and back cross reference to the amp versions that used it.  The OM is at least good enough with the block diagram to allow

...chassis or faceplate, a faulty 4558 is most probable.  The headphone approach is the fastest way to address this last one.  If a different series of preamp chip is used, a good source for ...