A: Yes. Unlike some “burn-in” programs from the 80s, modern diagnostic suites do not over-stress the ULA or transistor driver circuits. However, do not leave a pattern test running for 72 hours straight on an un-heatsunk ULA.
The diagnostic program is a perfect example of how the Spectrum’s simplicity and open hardware design turned a commercial machine into a hacker’s playground—where even failure could be debugged with beeps and patience. zx spectrum test program link
This is currently one of the most popular functional testing suites for hardware clones and original machines. It is an open-source project available on A: Yes
The test program outputs codes in the format: ERROR RAM 0: BIT 3 FAIL . The diagnostic program is a perfect example of
: Includes deep testing for lower/upper RAM, ULA, Z80 features, keyboard, and sound. It provides a "bad bit to chip ID" table to help you identify exactly which IC on the board needs replacing. Brendan Alford / Dylan Smith (ZX Diagnostics) : Project Repository : GitHub - zx-diagnostics Detailed Documentation : ZX Diagnostics Wiki/Manual Manual (Scribd) : ZX Spectrum Diagnostics User Manual
A 3.5mm mono-to-mono or stereo-to-mono audio cable.
Diagnostic programs and custom test ROMs bypass the standard boot sequence. They interact directly with the hardware to test: