Fix the mine's air purifier

Fix the mine's air purifier is a side quest in Fallout 2. To complete it, the Chosen One must retrieve the mine air purifier parts from New Reno, and then go into the mine itself to fix the purifier.

Detailed walkthrough
Talk to Zaius inside the house outside the Broken Hills mine's entrance. He will tell the Chosen One the mine needs parts for the air purifier and asks him to go to New Reno to pick them up. He can either take the reward for money, or decline and receive a combat shotgun when finishing the quest.

The mine purifier can not be fixed without the right parts so make sure the Chosen One does this quest before the who killed Richard Wright quest in New Reno if you're planning to frame Renesco.

Talk to Renesco the Rocketman in New Reno. Tell him Zaius' password. If the Chosen One doesn't, he'll need to fork over $200 for the parts ($100 with a Barter or Speech check).

Return to Zaius and he will ask the Chosen One to enter the mine to fix the purifier. The mine is filled with radon gas which will damage the Chosen One and his party for 10-15 armor-bypassing damage every couple of seconds. Wearing power armor will negate the damage. Use the parts on the clanking machine in the back (But watch out for the deathclaw!) for 1000 XP.

Rewards
Return to Zaius and he will give the Chosen One a City-Killer combat shotgun or $500 if he asked for a reward earlier.