We have recently migrated from Mark VI to Mark Vie for a frame V machine. Recently a diagnostic alarm -"toolbox ST application cannot retrieve diagnostic information from I/O pack, could not ping I/O pack PCMI-21:RackR(JA1)."
Can anybody tell me possible reasons?
The message text you posted isn't the actual diagnostic, it is ToolboxST saying it can't get a list of diagnostics from the pack. A lot of things could cause this, but most of them have more specific diagnostics or error messages. When you connect to the device in Toolbox, are there any errors in the log window, or items in red on the Status tab? Any controller diagnostics or diagnostics on other I/O packs?
GEH-6721 Volume I has a troubleshooting section which may help.