Some feature lamps on 1950s to 1970s Gottlieb games glow very bright, cook their bulbs and scorch nearby plastics or backglass art.

Gottlieb feature lamps burn too bright (28 V through a resistor)

Cause: These #47/#44 lamps run from the 28 V coil supply through a large sand resistor. The original 75 ohm value was chosen for 110-115 V mains; today's 120-125 V mains (or the high transformer tap) push too much current through. The resistors also break or drift.

Checks

• Check the sand resistor for breaks and measure its resistance.
• Note which transformer tap the game is on.

Fix

• Replace the resistor with a 125 or 150 ohm 10 W part until the lamps look right.

Systems

• Electro-mechanical

Related tips

• Gottlieb feature lamp burns out after switching to high tap
• Dim or flickering lamp sockets

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part One, Clay Harrell (pinrepair.com)