The number for Chicago AVM is 312-353-1059.
Once you get notified by Ohio or you see that they are past your priority dates, keep dialing this number to see if it was received in Chicago and if they even got a chance to update it in the AVM.
After dialing the #, Hit 1 for Perm cases
and intially select 2, and enter the employer phone number. It should be the same phone number that was mentioned on your ETA-750 forms. Once you enter the 10 digit employer phone number, all the cases for your employer will be listed in chronological order. If many people applied from your employer, then you should just make a guess about your case depending on the receipt date at chicago. In my case, mine was the only case from my employer, hence it was an easy guess.
Other alternative is to have your attorney call, (312) 793-6831 and mention your name and employer name, then you will get the appropriate information about your case.
Good Luck guys. Things finally started moving at CHI-DOL after a long time. So, you guys better hurry