While pinball playfields dominate most of my callout schedule, taking on a dedicated Defender arcade repair near Shepton Mallet was an exceptionally rewarding bench-and-field project. The client’s cabinet had two debilitating issues preventing gameplay: an unstable CRT monitor suffering from severe raster jitter, and an entirely dead sound board.

Diagnosing the raster instability pointed straight to dried-out electrolytic capacitors in the deflection and power regulation circuits of the CRT chassis. With classic arcade monitors becoming nearly irreplaceable, repairing rather than replacing is essential. I pulled the monitor chassis to the workshop bench, safely discharged the tube, and performed a comprehensive recap—replacing over twenty legacy capacitors with high-grade, heat-rated components, alongside reflowing cracked solder joints on the neck board.

For the audio failure, troubleshooting on-site was bypassed by installing a Williams sound board I had fully refurbished on my own bench. The client’s faulty board was pulled for shop diagnostics, and my fully tested board was installed into the cabinet’s audio harness.

Reinstalling the recapped monitor chassis into the cabinet, adjusting the focus and screen voltage on the flyback transformer, and connecting the audio board brought the cabinet right back to life. The vector-style raster picture snapped into crisp geometry with zero screen jitter, and the signature Williams explosions sounded completely clean. Seeing the owner finally play his all-time favourite arcade title after months of downtime made the bench work entirely worthwhile.

Looking to restore an arcade monitor or repair vintage game boards? [Get in touch through my contact page] to discuss workshop repairs.