Technos Double Dragon arcade pcb repair #2
The game would boot up with no errors on the self test, but then reset when you inserted a coin or shortly into the attract mode.
A couple of the main CPU program eproms initially gave slightly inconsistent results when read in an external programmer (different CRC’s each read) though when I tried again the next day they were 100% consistent. What was soon clear though was that using program eproms from a known working board made this board 100% reliable so new ones were burned and installed and everything fixed.
Quite an unusual fault to see original eproms from that era fail like this but they were definitely the problem.