This is the most reliable source for "Full Non-Merged" or "Merged" sets for 0.139u1. Users often upload complete collections here for historical preservation. Look for the MAME 0.139 Reference Set on the platform.
Understanding MAME 0.139u1: The "Gold Standard" for Mobile and Retro Emulation
Older PCs that struggle with the high CPU demands of modern MAME builds. Essential Setup Guide
Why target and not the latest version (0.270+)? Because every time MAME updates, the required ROM checksums change . A ROM that works perfectly in MAME 0.139u1 may be flagged as "missing" or "incorrect" in a newer version due to newly dumped, more accurate chips.