Fixing a broken part to make it work properly again
When to use
partial repair, temporary issue fix, cost-saving purpose
The nuance
Used when repairing a part of a machine, device, or object that is broken.
수리 (su-ri, suri) · 교체 (gyo-che, gyoche)
수리 means repairing a broken part, while 교체 means replacing the whole part or item with a new one.

One lane per word — no nested boxes, just the gist.
Fixing a broken part to make it work properly again
When to use
partial repair, temporary issue fix, cost-saving purpose
The nuance
Used when repairing a part of a machine, device, or object that is broken.
Replacing a broken or old part or the entire item with a new one
When to use
whole part replacement, aging part substitution, complete new item change
The nuance
Used when replacing a part or the whole item due to damage or aging.
자동차 엔진을 수리했어요.
ja-dong-cha en-jin-eul su-ri-haess-eo-yo., ja dong cha en jin eul su ri haess eo yo.
Repairing the broken part of the engine fits the meaning of 수리.
자동차 엔진을 교체했어요.
ja-dong-cha en-jin-eul gyo-che-haess-eo-yo., ja dong cha en jin eul gyo che haess eo yo.
Replacing the entire engine matches the meaning of 교체.
핸드폰 화면을 수리했어요.
haen-deu-pon hwa-myeon-eul su-ri-haess-eo-yo., haen deu pon hwa myeon eul su ri haess eo yo.
Fixing the broken screen part fits 수리.
핸드폰 화면을 교체했어요.
haen-deu-pon hwa-myeon-eul gyo-che-haess-eo-yo., haen deu pon hwa myeon eul gyo che haess eo yo.
Replacing the entire screen matches 교체.
고장 난 부품을 수리했어요.
go-jang nan bu-pum-eul su-ri-haess-eo-yo., go jang nan bu pum eul su ri haess eo yo.
Repairing the broken part of the component fits 수리.
고장 난 부품을 교체했어요.
go-jang nan bu-pum-eul gyo-che-haess-eo-yo., go jang nan bu pum eul gyo che haess eo yo.
Replacing the whole part matches 교체.
컴퓨터를 수리했어요.
keom-pyu-teo-reul su-ri-haess-eo-yo., keom pyu teo reul su ri haess eo yo.
Repairing the broken part inside the computer fits 수리.
컴퓨터를 교체했어요.
keom-pyu-teo-reul gyo-che-haess-eo-yo., keom pyu teo reul gyo che haess eo yo.
Replacing the entire computer matches 교체.
I ___ the broken smartphone battery.
The air conditioner's cooling function was broken, so I ___.
I ___ the old window with a new one.
The car tire was punctured, so I ___.