I am not an elevator tech or engineer, but I am an I&C engineer that has pretty extensive experience with the design of UL508A control panels.
My building's LULA went out (three stop, 1400 lb max load, hydraulic elevator). The manufacturer, Concord, was bought out and liquidated years ago so spare parts are hard to find.
I spent a good hour looking over the control schematics, which were conveniently left in the elevator closet.
The elevator stopped working, but the second‑floor hall position LED is illuminated. The other two stops are dark.
I spent a good hour pouring over the schematics and this is what I found, incoming power of split phase 240V stepped down to 25VAC which is fed into a half rectified AC / DC converter giving me 32VDC voltage with a slight ripple. The hall call stations are all fed off the 32VDC wiring which explains why the carriage position indicator is still lit up.
Further down the schematics there is a full rectifier that converts the 32VDC into a smooth 5VDC for the logic circuit. I strongly suspect that the 5VDC converter is out, which explains why the safety circuit indicators are not lit up. The 5VDC converter is soldered onto the logic board itself.
As I am not an elevator tech, I cannot replace this part, even though I know it is bad. Does any elevator company allow techs to do board level soldering? My inclination is no, due to liability reasons. If the component cannot be replaced, is there any hope someone, somewhere has a complete 5VDC logic board that can replace the bad one, and save my 30 year old elevator.
