Thanks again everyone. No blue light. Couldn't tell about the diagnostics as he'd lost the key. Think I'll give it a miss.

Thanks again
Mike

An unfortunately common ruse used when inspecting a pinball that isn't fully operational. Walk away when the seller tells you this.

Alternatively suggest that you come back with an electric drill and ask if you can drill the lock out......after all, he's lost the key right so the coin door lock is therefore useless......