The Pack-a-Punch Machine, otherwise known as just the Pack-a-Punch, is a staple of nearly every Zombies map released in the Call of Duty franchise.
Basically, what the machine does is that it upgrades your weapons into a more powerful version of itself, which, obviously, comes in very handy when you're battling waves after waves of the undead, as is the case in Firebase Z.
The second Zombies map to ever hit Call of Duty: Black Ops Cold War is set in a Vietnamese village and a military Firebase overrun by zombies.
Here's how you arm yourself with Pack-a-Punch weapons in Firebase Z so you can start the game right.
Where is the Pack-a-Punch Machine in Firebase Z?
Upon loading into Firebase Z, you'll find yourself in "The Village", where you'll also find the machine conveniently beside the office of Ravenov, who is, by the way, marked by a waypoint indicator, so all you have to do is to find him and go to the left of his office and that's it.
However, so as not to make things too easy for players, you'll have to power the machine first before you can use it.
To do that, you'll need to turn on the power first by taking the portal to the Firebase and head towards the Aether Reactors, which are marked by Dark Aether arrows pointing towards its direction.
You'll need to power on all three Reactors first, which involves spending a couple of hundred points and defending Collection Units from zombies.
Once you've turned on the power for all three of the Reactors, you'll have powered up the entire map and you can speak to Ravenov again, after which you can use the Pack-a-Punch to upgrade any weapon you have for 5,000 points (once) and 30,000 points (twice).