|''PCB Top'' ||''PCB Bottom'' || Description
|-
|[[File:Terje GX4000-MC0123B-K3.jpg|100px]] || || '''Board: 2700-017P-3, MC0123B, Copyright 1990, K3'''<br>R153 installed (near SCART connector)<br>handmade NR2 (between CPU and PSG)|-|[[File:GX4000_PCB_Top_(2700-017P-3_MC0123B_K3).jpg|100px]] || [[File:GX4000_PCB_Bottom_(2700-017P-3_MC0123B_K3).jpg|100px]] || '''Board: 2700-017P-3, MC0123B, Copyright 1990, K1'''<br>R153 installed (near SCART connector)<br>handmade NR2 (between CPU and PSG)
|-
|[[File:GX4000 PCB Top.jpg|100px|left]] || [[File:GX4000_PCB_Bottom.jpg|100px]] || '''Board: 2700-017P-4, MC0123C, Copyright 1990, K1''' ([[Media:Terje GX4000-MC0123C-K1 unrotated.jpg|other picture]])<br>R153 not installed (near SCART connector)<br>D135-D142 instead of NR2, R1/R2/C2 rearranged (between CPU and PSG)<br>bigger R181 (3 Watts), C32/D180 rearranged (near RGB monitor connector)