Simplex 4007es , isolator open CKT


I have problem in my Simplex 4007es panel, it show that there is a trouble " Card 2, loop A Isolator open CKT trouble"

I have checked the connection, there is no open CKT, the connection is class B. Also , i dont have the passcode to disable the fault.

Could any one help please ?

Thank you in advance.

Any one can help please .

just put the jumpers on 1 & 3, 2 & 4 for class B on the Loop card, and do a system reset


Thank you for your support,

Unfortunately, I have tried but not useful. I am not sure if the card is defected or the base of the detector not working.

I have checked the voltage in the card, It is ok 28 V.
Also, the voltage on the detector base is 28 V.

So really i am not sure what is the problem. if there is any suggestion i will be appreciated.

Thank you.