Test the eight photographed gongs and record the four that do not turn the crystals red. Wrong gongs reset the ringing, not which four are correct.
For the main quest, test during an eclipse after completing the crystal trials. A correct gong gives the positive sound/character cue; a wrong one flashes the crystals red. Leave uncertain gongs as “Untested”.
0 of 4 correct gongs recorded
Record only what you have tested. A previous failure does not shuffle the correct set.
Bridge bottom
Rope Bridge Area - At the bottom of the bridge, near the Pack-a-Punch pressure plate
Bridge top · left
Rope Bridge Area - At the top of the bridge, left of the PM63 wallbuy
Bridge top · right
Rope Bridge Area - At the top of the bridge, right of the PM63 wallbuy
Mud Room exit
Mud Room Area - Just outside the Mud Room toward Spawn
Spawn · M14
Spawn Room - Left of the M14 wallbuy
Minecart start
Minecart Area - Left of the start of the Minecart
Minecart slope
Minecart area: downhill from the cart, right of the zombie window.
Tunnel entrance
Minecart Area - Right of the tunnel
What to do after ringing the four correct gongs
Main quest: in the eclipse, use the Fractalizer to shoot the Minecart geyser crystal and catch the dynamite. Recharge the gongs, then shoot the Mud Room crystal to shrink the meteor.
Gameplay: Activision / Treyarch. Photographs and symbol references: mmmrkennedy, COD Zombies Guides and their credited community contributors. Shared-location photographs can show a remaster; the instructions and weapon landmarks here describe Black Ops (2010). See the map’s sources.