On placement at a bagging plant and the line I have been given came with nothing written down. CPU 1516-3 PN/DP, TIA V17. I need to change one timer and download it.

Going online works, I can watch tags and open the diagnostics buffer, all the read only stuff is fine. Download to device pops up "The CPU is protected. Enter the password", and I do not have one. The integrator who built it went out of business last year. I tried a different laptop with V17, and the download with the CPU in STOP, same both times.

Is there a way round this without the password, or is the CPU a brick for changes now? My worry is doing something wrong and losing the program that is running.