If you find a visible hairline crack on the PCB:
Unlike digital plugins, the hardware units had a literal "decay" built into them. The T4 cells were known to wear out every few years, leading to a loss of compression efficiency. This created a unique phenomenon where no two vintage LA-2As sounded exactly alike. This variance is the "deep story" behind why "cracked" or vintage units are so sought after—they each have a unique, aged character. 4. The Waves CLA-2A: Modeling a "Golden Unit" Waves Audio