Uploaded August 2026 | Updated September 2026, 2 weeks ago

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A repair attempt on a dead Sinclair ZX Spectrum Issue 3. I perform a visual inspection of the mainboard and test the power supply voltages, finding them to be correct. Using a thermal camera, I check the ICs and notice the RAM chips are warming up, but the ULA remains completely cold. I hook up the oscilloscope to check the clock signals and find no activity on the 14MHz input or the 3.5MHz output. Suspecting a faulty crystal, I swap it out to test, but the board remains unresponsive. Finally, I swap the ULA with a known working spare, which confirms that the original ULA has failed. Without a spare ULA to sacrifice, this board will need to go back into the repair pile or be returned as is.

Links mentioned:

Ready Player 2 Podcast
youtube.com/@UCxMoJPXOsD5TenoqgsXKzIw

Break Into Program
breakintoprogram.co.uk

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#ZXSpectrum #RetroComputing #techrepair

00:00 Introduction and visual inspection
02:26 Powering up and checking voltages
03:35 Thermal camera inspection
04:32 Oscilloscope testing the clock signals
07:09 Swapping the 14MHz crystal
08:41 Testing with a known working ULA
10:31 Conclusion
12:08 Ready Player 2 Podcast