Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
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When an 'ERROR RAM' appears on power-up, it usually means a severe problem with memory handling or basic memory management, or sometimes simply memory not reading, inside the printer.
It is a fatal error and requires considerable remediation actions before the printer will work again.
The usual measure is to open the rear cover, and - observing anti-static-discharge precautions, which are absolutely essential and this cannot be emphasized enough - re-seating the RAM modules in their slot(s).
Are you prepared to do that? it's good to have a delicate touch, not wear anything woolen, and also have considerable knowledge of anti-static discharge precautions.
If so, I can instruct you... but be warned again, it's best to have a qualified electronics technician do the RAM reseating.
(Also, there is a slight possibility that one or more RAM modules have been removed from the printer, or that - if RAM modules have been changed or new ones installed lately - that the changed or new modules are faulty.) Let me know, please. Thanks.