yes sta-19 is another model name/number for this. Nothing came up from my google and forum search for this particular one.

Hi, I’m looking for the service manual or schematic for a Realistic 31-1975A Stereo Receiver. If anyone has a PDF they could post I would greatly appreciate it. Thanks

Can you post a schematic of the circuit you are using it in? Maybe it’s just due to the precision limits of the meter you are using to take the measurement? Depending on the circuit and due to the inherent high gain of those op amps, if the output is zeroing it seems like the op amp isn’t “seeing” any voltage difference between the inverting and non-inverting inputs.

That’s a good idea, I’ll check that out next week, Thanks...

yeah, I think this is most likely the case too. It’s only four cars and eleven stops so 44 potential culprits, lol!...

Yes there is a big filtering cap on the driver board. I don't have a board level schematic, but I have attached a picture of the board from the MCE elevator controller website:

[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3567557}[/ATTACH]​Yes there is a big filtering cap on the driver board. I don't have a board level schematic, but I have attached a picture of the board from the MCE elevator controller website:

[ATTACH=JSON]{"data-align":&...

Here you go:

[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.jpg","data-attachmentid":3567524}[/ATTACH]​
As I mentioned above the relay coil voltage needs to match the voltage of the pump power, and the contact rating for the relay you select should be able to carry more current than the pump will draw. Relay contacts will also give a horse power rating which should be more than the horse power of the pump.Here you go:

[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.jpg","data-attachmentid":3567524}[/ATTACH]​...

Correction it would be the normally closed contact, not the normally open to reverse the logic, sorry for the confusion. I’ll make a drawing of what I’m saying and post it here soon.

An external relay would easily do what you need it to do. You have to find a relay with a coil voltage equal or nearly equal to the voltage going through the switch currently. Take one wire from the switch and land it on the relay coil base, the other side of the coil would be wired to ground if it is a ground referenced DC, or to whatever common the DC is referenced to. Then parallel the power DC wire to one of the relay’s common terminals and take a wire from a normally open relay contact to the power input of the pump. You have now inverted the logic of the float switch. Omron sells some...

I have attached the relevant areas of the schematics. The building 3 phase 480vac powers the elevator controller, it is then transformed down to single phase 120vac, which is again stepped down and full wave rectified to unfiltered 24vdc. The unfiltered 24vdc gets plugged into the car and hall fixture driver board, and is filtered at the driver board to a steady 24vdc with about 200-300 mVac ripple. This filtered 24vdc goes to each floor's serial hall fixture as power. Each floor's serial hall fixture has a unique address that can be set by an onboard dip switch. Not 100% sure but the data signal...

Hi,

My name is Matt. I’m brand new to this forum, and it looks like a great resource! I’m an elevator technician with hobby level interest in home audio electronics repair. Hope to learn a lot and have a good experience here. I’m pretty good at troubleshooting electronics, and quite experienced troubleshooting a wide variety of elevators and escalators mechanically and electrically including the high voltage power and low voltage logic systems of this type of equipment.

Cheers