ZX Spectrum 128K "Toastrack" IC Replacements and SMD Soldering (Part 2)

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Last time we figured out the problems in this Sinclair ZX Spectrum 128K Toastrack, but we had to replace multiple chips to get it working. Today we're going back and we're going to try to figure out suitable replacements for the ZX8401/PCF1306P, the ULA, and the ROM.

As part of that, we dig into what exactly the ZX8401 does and the details of the ZX Spectrum memory addressing, and then we proceed to do some SMD soldering (and desoldering!) for a replacement board.

Chapters: 00:00 Intro 00:19 Patreon announcement 00:45 ZX8401 01:41 Memory addressing in the ZX Spectrum 05:27 Building a ZX8401 SMD replacement 09:36 Diagnosing faulty ZX8401 replacement 13:20 SMD desoldering 15:02 ULA problems 18:26 RGB Scart cable 20:24 Comparing and replacing the EPROM 23:54 Conclusion

José Leandro Novellón PCG1306P design http://trastero.speccy.org/cosas/JL/pcf1306p/PCF1306P.html

Order a PCF chip replacement: https://www.ebay.es/itm/224111543392

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#zxspectrum #repair #sinclair ... https://www.youtube.com/watch?v=T9CXK8z4QdE