This machine has worked perfectly for years. Today I replaced the belt. This is a little involved. After finished, the machine ran just fine for a few hours, and printed some demos. Now I updated the IP address to a new subnet. And then the machine will no longer boot. Does anyone have any experience with this?
Did reseat the cable mentioned.

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System Error 0b0004 00000011
The manual says:
Problem APS Failure. (Air Pressure System)
Description:
Corrective Action: Try the following:
Check that the cable from the Ink Supply Station (ISS) PCA to the Ink Supply Station is correctly connected.
Faulty APS. Replace the APS Page 8-67.
If the error code continues, replace the Main PCA Page 8-81.
WARNING Only replace one component at a time and check if the error has
gone before replacing another component. Using this procedure
you will be able to determine exactly which component failed.