Miprom 21 Duplex

I maintain a Miprom 21 duplex from 93. The customer is complaining that intermittently the hall call buttons will start activating by them selves and the elevators start running to different floors and the doors will open and close and even shutter back and forth. I checked the card cage voltage which is 26 v dc. This does not have a separate group controller, only the cards for hall calls which are in both controlls. I have never seen this happen before but since multiple people have complained it must be happening. Does anyone have any ideas or suggestions? Thanks in advance.

I guess I would start looking over the connections. Wiggle the input and output board terminals, unplug and plug all the boards into the card rack including the Smart boards and associated buss wires. How often does it happen? these are tough ones without it happening while your onsite.

I haven't reseated the boards yet but I did push on them and pull on all the wires to see if I could find an issues. It probably occurs once every few hours but I haven't seen it happen yet.

Check for any voltage on your input rack. You put ss(120vac ) to make call work. a blown diode can give you a back feed on your rack.

Any security lock out-card reader feature on this system (for the hall calls)?

If the elevator loses hall calls it will service different floors that are programmed in the field adjustable parameters. That would explain the random calls. You must be intermittently losing the hall calls or theMiprom thinks they are lost. It doesn't know what to do because they are all outputting at once. A bad input or output can cause this. Input the calls one at a time and see if one is causing this. A lot of times a bad input or output will turn all of them on.

there is an input and output test you can run from the tool. defiantly sounds like a bad input/out put board, possible for bad card rack but doesn't sound like it as it is so random. Card rack issues are more obvious.

Thanks for the info. I haven't been back there yet, maybe they haven't experienced it in a while, but I'll check these things.