Is money earned from maintaining and selling computers suspected of being stolen, or obtaining spare parts as payment for maintenance, considered illicit gain (haram)?

It is impermissible to repair stolen devices, sell them, or deal with their owners in any way, because it constitutes aiding in sin. Allah Almighty says: "And do not cooperate in sin and aggression." And dealing with devices whose unlawfulness is suspected by more than 90% means dealing with the unlawful, because the predominance of suspicion takes the place of certainty. Therefore, one must repent and seek another profession, for whoever abandons something for the sake of Allah, Allah will compensate him with something better. And Allah Almighty says: "And whoever fears Allah - He will make for him a way out And will provide for him from where he does not expect."