** MC6850 pin 7 (/IRQ output) is connected to Vcc, but should be left unconnected.
** The signal marked 153.8MHz (in v3) is, of course, 153.8kHz (4MHz/13/2).
** The photo seems to show v1 and uses 1.8432MHz crystal, whilst schematic v1 uses 10MHz (?)
* Note: The Z80 CPU shown in schematic is your CPC's built-in CPU (mounted piggy-back on the AMSSIO cart)