One step closer to the problem :-)

Hello Dut_Norshi So! The fact is that the Spectrum started working for me when I unsoldered all sorts of devices (keyboard, tape recorder connector (removed altogether) and cleaned the board. I have 13 wires going from the keyboard to the connector (main keys) and separately There are 3 wires - ground, reset and, as I assumed, magic. So here it is. Now I soldered the ground, reset and this potential magic to the XP1 connector according to the diagram. I turn it on Spectrum - doesn't work! The same cubes appeared as before! I turn it off, unsolder it potential magic from XP1:A4, turn it on - it works! Touched this wire XP1:A4 -- the screen began to become overgrown with cubes! It looks like the problem was with this "magic". Or there is no magic on the keyboard or something was connected incorrectly! Does anyone have any thoughts on this? :v2_conf2: