Quoted from Theonlylilo:
Good morning to everybody! Just a little clarification before my summer holidays
On Ebay I won an auction for 10 PIAs 6821... good price, for a Chinese counterfait parts of course! From the pictures looked original but once in my hands... ok, now I have them here...
Is not the first time that I try them on bench (WMS driver board, with Leon test rom), they work fine but once in the flipper... problems problems problems...
How is it possible? The bench test should be reliable, right?
Thanks for suggestions...
You would think so.. I have written some test ROMs from scratch, you could try them on the bench but they were designed to run in the game. Give them a try and see if they help you find what the problem in the flipper is.
You can download them from here: http://pincoder.reversion.ca
There is also a thread on this site where you can leave some feedback: https://pinside.com/pinball/forum/topic/new-williams-system-6-in-game-test-roms
Let me know how you make out!