Мастер поменял патрон, протёр столешницу и сказал, что теперь всё работает нормально.

Мастер is a common Russian word for a skilled worker, repair technician, handyman, or specialist who fixes or installs things. In this sentence, it most naturally means the repairman / technician.

Grammatically, мастер is in the nominative singular because it is the subject of the sentence: he is the one doing the actions.

Поменял is a perfective past-tense verb. Perfective verbs usually present an action as completed.

So:

• менял = was changing / used to change / changed (with focus on process or repeated action)
• поменял = changed / replaced (successfully, as a completed action)

In this sentence, the technician finished the action, so поменял fits naturally.

Also, поменял is:

• past tense
• masculine singular
• agreeing with мастер

Патрон is a word with several meanings in Russian, so learners often notice that it seems ambiguous.

Depending on context, it can mean things like:

• a cartridge
• a light socket
• a drill chuck

In this sentence, the exact meaning depends on the situation you were given in the translation or surrounding context. Russian often leaves this kind of detail to context.

Grammatically, патрон is:

• masculine
• inanimate
• here in the accusative singular

Because it is an inanimate masculine noun, its accusative form looks the same as the nominative:

• nominative: патрон
• accusative: патрон

Because столешницу is the direct object of протёр.

The base form is:

• столешница = countertop / tabletop / worktop

This is a feminine noun ending in -а, and in the accusative singular that ending changes:

• nominative: столешница
• accusative: столешницу

So the sentence uses столешницу because the master wiped the countertop.

Протёр is again a perfective verb, showing a completed action: he wiped it down.

Compare:

• тёр = was rubbing / rubbed
• протирал = was wiping / used to wipe / wiped repeatedly
• протёр = wiped clean / wiped down completely

The prefix про- often adds a sense of carrying the action through to completion.

So the sentence presents a sequence of completed actions:

1. he replaced something,
2. he wiped the countertop,
3. he said that now everything works normally.

The punctuation reflects the structure of the sentence.

The first part is a list of actions by the same subject:

• Мастер поменял патрон, протёр столешницу и сказал...

Russian often separates parts of a series like this with commas, especially when one conjunction links only the last item.

So this is essentially:

• changed X,
• wiped Y,
• and said Z.

Then there is another comma before что:

• сказал, что...

That comma is required because что introduces a subordinate clause:
he said that...

Because the subject мастер applies to all three verbs.

Russian, like English, often avoids repeating the subject when the same person performs several actions in a row.

So this means:

• Мастер поменял...
• (мастер) протёр...
• (мастер) сказал...

The repeated мастер is simply omitted because it would be unnecessary.

Сказал, что... is the normal way to say said that...

• сказал = said
• что = that

So:

• сказал, что теперь всё работает нормально = said that now everything works normally

If Russian wanted to emphasize telling someone, it might use a different structure, for example with an indirect object:

• сказал мне, что... = told me that...

But here the sentence only reports what he said, not who he said it to.

Because всё and все are different words.

• всё = everything / it all
• все = everyone / all people, or all items in a plural group

Here the meaning is everything / the whole thing / it all, so Russian uses всё.

Since всё is grammatically singular, the verb is singular too:

• всё работает = everything works

If you said все работают, that would mean everyone is working or all of them are working.

Because нормально is an adverb, and it modifies the verb работает.

• нормальный = normal (adjective)
• нормально = normally / properly / fine (adverb)

In this sentence, the idea is:

• работает нормально = works normally / works properly / is functioning fine

An adjective like нормальный would need to describe a noun, not a verb.

Теперь means now, and its position is flexible. Russian word order is freer than English word order, although not random.

Here:

• что теперь всё работает нормально

sounds natural and neutral:
that now everything works normally

Placing теперь early helps frame the statement as the new situation after the repair.

Other word orders are possible, but they may shift emphasis:

• что всё теперь работает нормально
• что всё работает теперь нормально

The version in your sentence is the most straightforward.

In the Russian past tense, singular verbs show gender.

Here we have:

• поменял
• протёр
• сказал

The ending pattern shows masculine singular past tense.

Compare:

• masculine: сказал
• feminine: сказала
• neuter: сказало
• plural: сказали

Since the subject is мастер, a masculine noun, the masculine past forms are used.

Yes, very much so.

Russian often uses perfective past verbs to present a chain of finished actions:

• поменял — completed
• протёр — completed
• сказал — completed speech act

This gives the sentence a clear narrative flow: He did this, then this, then this.

If imperfective verbs were used instead, the tone would be different: more about process, repetition, or background action rather than a neat sequence of completed events.