i have a few computers that i want to repair (2 x zx spectrums, an atari 800 and an atari 2600) and im sure its the cpus that are faulty. i have run diagnostic tests on all these systems and swapped out all the chips except the cpus. i just dont have any more of these in stock. any help would be appreciated.
This is a slow thread... ZX Spectrums rarely lose the z80. Most commonly they lose the -5v and 12v rails, and then the 4116 RAMs stop working and die... The most common repair on a Spectrum is fix the rails, then replace the faulty 4116 chips.