Canon ImageRunner 5020 losing cassettes

[Guest]

I have a small copy shop and one of my best workhorse copiers, the Canon ImageRunner 5020 with 4 million copies, has developed an issue I cannot fix. The copier seems to keep losing the cassettes. It started with the ledger tray and will no longer recognize it. A month or two later, the legal tray ID is lost, then the top 2 letter size trays disappeared.
I got into the service mode and reset the trays and only the Letter trays will stay recognized.
Another issue is a metal on metal grinding sound when the copier is picking up paper from the cassettes. It DOES NOT make that sound when feeding from the bypass/manual feed.
Could these two issues be related?
The main PCB board has been replaced, to no avail. My next try is either the DC Controller board and/or the Cassette pickup drive assembly, both of which are hard to find and expensive
Has anyone ever experienced this issue before?

[charm5496]

so right now the machine is not recognizing the two letter size trays at all and the settings for the cassettes do not hold?

Start with your DC controller....that is where all your communication goes through, but keep in mind that your machine is downhill side of its better days having 4 million on it. You could have a wiring issue, worn sensors for the cassettes and decks or a combination of things going on. Might be better off paying the money and having a trained tech take a look at it, or invest that money in a newer machine with a lower meter count it.