Yikes.... Brand new keyboard with its brand new strips scratched! However, I have to concur with RWAP 100%. He(RWAP) deserved an applaud from each of you! I am very happy to know that you checked the continuity from pin 3 and ULA pin 29 and it is OK.
I have checked both stripe sockets with a cardboard playing in and out with some contact cleaner and they look fine. I tested also with the original stripe membrane, inserted it and pulled back several times with no damage on it. I think it will work well with a new keyboard membrane of better quality
However, I have to concur with RWAP 100%. He(RWAP) deserved an applaud from each of you! I am very happy to know that you checked the continuity from pin 3 and ULA pin 29 and it is OK. 
Was definitely a bad quality issue. ZX81 back to business! Thanks a million 
