To check the memory module, perform the following:a. Power the printer OFF (using the main power switch located on the rear left side of the main body).b. Remove any additional memory modules, which have been installed on the IP unit.c. Power the copier ON. If, the IP boots up successfully one or more of the memory modules has failed. Replace the memory modules [MU-404/64MB] (Item#950218) or [MU405/128MB] (Item #950219) as necessary.