A fuse blows immediately at power-on, for example F4 on Black Hole or Haunted House.

A bottom-panel fuse blows the moment the game is switched on

Cause: The bridge rectifier feeding that fuse has shorted.

Checks

• Diode-test the bridge: black lead on +, red on each AC lug, expect 0.4 to 0.6; then red lead on -, black on each AC lug, expect 0.4 to 0.6.

Fix

• Replace the bridge with an MB3502 or MB3504 lug bridge (35 A, 200 or 400 V); a higher rating is fine but never lower.

The bottom panel carries 120 V AC from the wall; unplug the game before touching the line filter, fuse block or transformers.

Systems

• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B

Related tips

• First power-up, step 1: check the bottom-panel fuses
• Bottom-panel bridge rectifiers and fuses
• Replacement bridge rectifiers
• Haunted House and Black Hole fuse panel
• Quick diode test of a bottom-panel bridge rectifier
• Check the 80B bottom-cabinet 10,000 mfd filter capacitor
• System 80B ground lost at the transformer panel plugs
• Haunted House playfield fuses

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)