Mitsubishi AOJ2

I have an A0J2 Mitsubishi PLC with Eprom on a robot press line. If I change it out with a A0J2 without an Eprom, we have troubles with our press line. Things are acting funny. Are there some difference with the Eprom version compared to the one without the Eprom? When the PLC was changed out with the non Eprom one, the program loaded okay and there seemed to be no problems. When production runs, there are just a lot of weird problems going on that makes us put the original PLC with the Eprom back in. When we do that, there seems to be no more problems.
Tim

So to paraphrase: Is there a difference between an A0J2 processor with and without an EPROM fitted ?

I cant imagine there is but its 10 years since i have even seen an A0J2 and my memory is not that good

One for the older Mitsubishi experts i think !!