Home Forums General Discussion Technical Questions Northern 3200 FSP

I’m having trouble with a 3200 & PPU setup. I’m not getting fast speed, the FSP signal from the PPU to the controller. Car runs, does single and multiple floor calls, knows it’s position, just not fast speed. Won’t come up from leveling speed. Problem is, there’s no write up about PPU signals or inter workings of it.

Does anyone know what the PPU is looking for to send out the high speed signal? Or is it likely a board issue?

The A contactor is energized sending 120vac to the opto- coupler on the hyd 9806 board which converts 120vac to 24vdc
The signal is then sent to input I78 PPU FSPX
Output O45 then goes high to pick up FSP relay




Check the NO contact on the A contactor if it’s not that contact then it’s going to be the opto coupler on the main relay board that converts signal from AC to DC

Thank you for the response, and yes, that is my issue. The FSPX signal up from the PPU to the controller isn’t there. Or, more accurately, flickers in and out at points.

That’s really what I am trying to figure out. What does the PPU need to see to send that signal? I’ve tried swapping around some of the I/O cards inside the PPU and it actually does have some effect on the frequency of the flickering. But I’m not sure if that’s dumb luck, or if it’s a problem with the bottom motherboard, or if there is some other signal the PPU needs to first see to send fspx.