PCB Repair: Speed Buggy/Buggy Boy – PhilWIP

Content introduction

In this detailed PCB restoration story, the authors share their personal experience restoring the classic arcade game Buggy Boy, a game with which they have a deep connection since its addition to MAME in 2006. This piece of content stands out for its technical depth, detailing the complex process of diagnosing and resolving multiple issues on the game’s large and complex circuit board. The authors’ expertise lies in their ability to accurately locate and correct faults through circuit diagrams and using various tools such as oscilloscopes and logic analyzers. Notably, the guide addresses common problems with vintage hardware, such as the notorious failure rate of Fujitsu ICs, and provides specific fixes for problems encountered. For retro gaming and electronic restoration enthusiasts, this article is important because it not only provides a glimpse into the challenges of maintaining classic arcade games, but also serves as a practical guide for similar PCB restoration jobs.

Automatic summary

– Buggy Boy is a complex on-board circuit in which the sprite hardware is inactive.
– The FMA3 signal remains low, causing the Elf hardware to not work properly.
– After replacing the CRTC, the sprite returned to activity, but with some glitches.
– The LS378 at IC20 on the video board failed, causing the tile map layer to turn black.
– Removing all Fujitsu ICs and replacing them with new LS378 improved the situation.
– The output of the 7497 binary multiplier floated, affecting sprite scaling.
– Replacing SN7497N fixed sprite scaling issue.
– Another glitch occurred, causing a specific percentage of sprites to malfunction.
– IC201, a 74S00 four-input NAND gate whose output behaves like a NOR gate.
– Replacing IC201 solved the problem.
– After more than 24 hours of burn-in testing, no further failures occurred.

Original link: https://philwip.com/2024/03/22/pcb-repair-speed-buggy-buggy-boy/