jipju-inege surireul butakhaessdeoni gojang nan jeongureul baro bakkwo jwosseo.

It is 부탁했다 + -더니.

• 부탁하다 = to ask a favor / request something
• -았/었더니 often means when I did X, (then/as a result) Y happened

So 부탁했더니 means something like:

• I asked, and then...
• After I asked, ... happened
• I asked, and as a result...

In this sentence, it connects asking the landlord for repairs with the result the landlord immediately changed the broken light bulb.

It often carries a nuance that the speaker personally experienced or observed the result.

에게 marks the person who receives the request.

So:

• 집주인에게 부탁하다 = to ask the landlord
• literally, to the landlord

A native English speaker may expect something like a direct object, but in Korean the person you ask is commonly marked with 에게 or 한테.

• 에게 = neutral/written-leaning
• 한테 = more conversational

So 집주인한테 수리를 부탁했더니 would also be very natural in speech.

Because 수리 is the thing being requested.

• 수리 = repair, repair work
• 수리를 부탁하다 = to request repairs / to ask for a repair

So the structure is:

• A에게 B를 부탁하다
• ask A for B

Here:

• A = 집주인에게
• B = 수리를

That is why 를 appears after 수리.

Yes. That would also be natural, and it is a little more explicit.

Compare:

• 수리를 부탁했더니 = I asked for repairs
• 수리해 달라고 부탁했더니 = I asked them to repair it

The original sentence is slightly more compact and noun-based. The -해 달라고 version spells out the requested action more directly.

Both are common.

Not exactly. -더니 is more specific than a simple and then.

Here it suggests:

• the speaker did something first
• then the speaker saw the result
• often there is a cause-and-result or discovery feeling

So 부탁했더니 ... 바꿔 줬어 is not just a neutral sequence. It feels like:

• I asked, and then sure enough / as a result, they changed it

This pattern is very common when talking about what happened after doing something.

고장 난 comes from 고장 나다.

• 고장 나다 = to break down / stop working / go out of order
• 고장 난 = broken / that has stopped working

The -ㄴ form turns the verb into a modifier before a noun.

So:

• 고장 난 전구 = a light bulb that is broken / a broken light bulb

This is the same kind of pattern as:

• 문 닫은 가게 = a store that closed
• 잘 익은 과일 = well-ripened fruit

The standard spacing is 고장 난, because it comes from the verb phrase 고장 나다.

So:

• dictionary form: 고장 나다
• noun-modifying form: 고장 난
• standard spelling: 고장 난 전구

You may still see 고장난 in casual writing, but 고장 난 is the standard spacing.

Yes, it sounds natural.

In Korean, 고장 나다 is used broadly for things that do not work properly anymore. So for a light bulb, 고장 난 전구 can mean:

• a broken bulb
• a bulb that stopped working

In everyday Korean, you may also hear other expressions depending on the situation, but 고장 난 전구 is understandable and natural.

바로 here means right away, immediately, or on the spot.

So:

• 고장 난 전구를 바로 바꿔 줬어 = they changed the broken light bulb immediately

It adds the nuance that the landlord responded quickly.

Its position is also natural: it comes right before the verb phrase it modifies.

Because -아/어 주다 adds the meaning of doing something for someone.

So:

• 바꿨어 = changed it
• 바꿔 줬어 = changed it for me / did me the favor of changing it

In this sentence, 줘 shows that the action benefited the speaker.

That is very common in Korean and often sounds more natural than leaving it out when someone helps you.

They are contracted spoken forms.

• 바꾸다 → 바꾸어 → 바꿔
• 주다 → 주었어 → 줬어

So:

• 바꿔 줬어 is the shortened everyday form of 바꾸어 주었어

This kind of contraction is extremely common in normal speech.

The subject is omitted because it is easy to infer from context.

In this sentence, the understood subject of 바꿔 줬어 is the landlord.

So the logic is:

• I asked the landlord for repairs
• the landlord changed the broken light bulb right away for me

Korean often leaves out subjects when they are obvious, much more often than English does.

줬어 is informal, casual speech.

It is natural when speaking to:

• a friend
• someone younger
• someone close to you

More polite versions would be:

• 집주인에게 수리를 부탁했더니 고장 난 전구를 바로 바꿔 줬어요.
• or more formal: 집주인에게 수리를 부탁했더니 고장 난 전구를 바로 바꿔 주었습니다.

So the original sentence is casual everyday spoken Korean.

Yes, that is natural.

수리 can refer broadly to repair work or fixing a problem. In real life, fixing the problem may involve:

• repairing something
• replacing something
• adjusting something

So the sentence means that the speaker asked for repair/help with a maintenance issue, and the landlord solved it by replacing the broken bulb.

That combination is completely normal.