BryanMcPhail.com

Professional software development, amateur BMW tinkering, old arcade game stuff

By

Namco Galaga arcade pcb repair

A pair of Galaga boards, both of which displayed garbage and continually reset. First thing to check is the usual basics – do the CPUs have a clock signal, is the reset line working correctly, is the data on the ROMs valid? Between both boards 3 failed CPUs and 4 bad eproms were found. With them replaced problems such as random resets and missing sounds remained – but after a lot of debugging it all came down to dirty sockets or corroded chip legs. After a clean-up both boards were stable.

20180821_083624

20180821_083616

One fault remained on one of the boards – for all sprites only the blue channel was displayed – unfortunately this turned out to be a failure of the sprite color PROM at location 1C on the video board. A replacement was pulled from a bootleg Gallag in order to fix the original board.

20180818_145809

20180819_170901

20180819_171813

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>