For the SMD transistors I used 3904 (MMBT 3904LT1G) - they seem to work well.
Also the fixed reset circuit with the 2 diodes and pullup resistor doesn't work reliable here.
After cutting the incorrect connection between D4 and A15 the sinclair message finally shows up now
I'm still getting some random junk pixels and the machine crashes after a few seconds, but that might be due to the fact that I haven't fully decoupled the TRDOS section of the board yet.
D16 can be substituted with a CD4069, D12 also works with a CD4520 (MC14520 aren't that easy to obtain here).
I'm currently layouting a board to add 128K support + AY + Kempston - would anyone be interested in that?
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