For diagnosing and testing a ZX Spectrum , several modern and vintage utilities are available. These tools help identify hardware faults in RAM, ROM, the ULA, and other key components. Primary Diagnostic Tools ZX Diagnostics (Brendan Alford)
A message like ROM CRC error: expected 0x12AB, got 0x44FF means your ROM chip (usually a 2364 or 27128) has a bit-rot or a failed address line. Replace the EPROM. zx spectrum test program link
A “test program link” commonly refers to a packaged or documented way to obtain, load, or chain (link) one or more test programs together — either as a loader that sequentially runs multiple tests, or as a link/reference (URL/archive) pointing to test program resources. For diagnosing and testing a ZX Spectrum ,