piss take aside its Imo a sterling 10. I'd agree its crap and should be replaced. I'd get an old Scantronic 9xxx which would be better. the sterling 10 like all Pyronix panels are proper bad.
No I think you misunderstood. If you program the panel as eol then you need to fit the resistors in the devices. You are using it (it appears) in non eol mode which enables the common AT circuit. It is that circuit that has a fault you will have to trace it one by one to find it
to be fair we get lots of trade requests from people that are not trade or don't read and assume that asking for will do. Pete volunteers to do the vetting.