BUILDING, TESTING and almost FIXING a backplane for the ZX Spectrum

I recently had a cause to fit more than one expansion to my ZX spectrum at the same time so went on the hunt for some means of doing it. After stumbling across a 6 way backplane on project speccy I downloaded the gerbers, ordered the boards and attempt to get it working! So join me as we head far deeper down this Sinclair Rabbit hole than I thought possible. Links Project Speccy - https://projectspeccy.com/ Spectrum schematics - https://spectrumforeveryone.com/technical/zx-spectrum-pcb-schematics-layout/ Parts - https://www.retroleum.co.uk/ Music @Momentvm Cathode Ray Gun - https://www.youtube.com/watch?v=J-wUZp9XXbc CRG Links CRG X (Twitter) - https://twitter.com/YT_CRG CRG Patreon - https://www.patreon.com/user?u=13919007 CRG Discord - https://discord.gg/3hEzUxTxWV Chapters 00:00 Intro 02:52 Assembly 05:13 Fitting and Voltage 06:17 The problems begin 07:29 Other problems 11:27 Back to the backplane 12:57 Swapping ram and LS157s 14:26 128k ram mod 16:44 Loading problems 19:15 The plan 21:30 Address bus buffer testing 24:12 Fireworks 26:18 Termination 30:39 More loading woes 34:22 One last try 39:53 Conclusion