Bench testing a trough transmitter board

The trough transmitter board needs only 12 V DC, so it can be checked on the bench with a 12 V supply and an infrared card or camera. A dead LED points to a broken blue resistor, a broken trace or the LED itself.

Systems

• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• Replacing trough transmitter and receiver optos
• Old and new WPC ball trough designs
• Opto ball troughs from Indiana Jones on
• Remounting early trough opto boards on grommets
• Test the shooter lane switch when chasing trough faults
• World Cup Soccer and later trough opto boards carry only the optos
• Random multiball from cracked blue resistors on trough boards
• Intermittent trough sensing: cracked header pin solder

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Three, Clay Harrell (pinrepair.com)