Its been awhile, try to go ccw on the check. I believe thats least resistance. If not go the other way. Its like a hydraulic valve in the tank w/o an adj sheet if one way doesn't make it better go the other way in small increments.

Have you removed power from the unit and moved the doors by hand to check for binding/interference?

you would be correct.definitely back the adjuster out a full turn counterclockwise..if it slams in the open.take it in for dampening...if all else fails you may have a problem with the engine.the gears inside can have problems over the years..that part is still readily available..

Which controller?
Is the door motor DC?

Generally with these things its trial and error. You must ALWAYS mark where an adjustment is BEFORE moving it. This way you can put it back to where it was if it doesn't make a difference. This applies to all adjustments on anything ie wires, adjustment screws etc. On this issue im pretty sure that with hydraulic adjustment screws turning them into the barrel compresses oil, so will increase tension and vice versa for the other way. that's the way I have generally go but I always mark/measure(the screw length from the base) so I can put it back if I need to. Doing this and testing is the easier way to find out if its a door check issue. let us know how you go.

Ps. make sure you haven't got something stuck in the car door track. I've done that before too!! 😠

The door motors are indeed DC and the controller type is a NI2CL.As for the door operators, I am not sure which screws are the actual adjusters. At each and of the door check area on the operator there is a small screw (or possibly a vent) on top of the door check as well as a large set screw on either end of the door check which possibly is just a cap. I believe that the smaller screw on top is the adjuster but I wasn't sure if the set screws on the end of the operator function as some sort of stop or adjuster. If all else fails I will probably leave the operator as is since we will be doing a modernization on this car in January or February and I am trying to keep this car running until then.

Thanks to all for their replies and all the valuable advice.

PS I had previously cleaned the gate tracks and lubricated all the pivot points and chain on the operators. Although both operators respond the same to a door open command (stopping about 1 1/2 inches short of fully open) on one of the operators it is very difficult to manually open and close the door while on the other operator the door opens and closes very easily manually. I thought this might be related to the checks but I also thought there might be an internal problem in that operator.I was hoping to correct the problem when I adjust the checks, I would hate to have to replace the operator this close to doing the modernization.

Thanks again

Ok mate it sounds as if you have some issue here and it depends on how detailed you want to get. I do think the adjustments screws are on the top. If that doesn't help then I'd unbolt the car doors from the operator and then try to open the operator and that should tell if its the operator or not. You may have a bearing on the car doors that may be stuffed! It actually doesn't take much to open up the gearbox of a PDO to check inside and they can get so clogged up so that might reveil whats going on. As I said it depends on how much you want to go into it. I reckon you've got a bung main bearing gone. I did manage to find this about some Otis operators but the pdf stops before this operator is shown. maybe contact them for details?

www.unitecparts.com/wp-content/.../03-DoorOperators-W_Part1.pdf�

Are they using positive monitoring for the door operator. Or is their some type of door open/close limits.

There are usually brushes in a DC motor. Check the hertz layer on the door motor commutator and brushes.

I am thinking that Uppo72 is on the right track. The motor seems to operate just fine even with the tightness of the one door. I have checked and lubricated the rollers so I don't think the problem is there. If I can get the customers approval (work = $) I think I will pull the operator and examine. As for the monitoring the door there are no limits to set open distance its all done through the capacitors and resistors as far a I can determine. Realistically I am just hoping to keep it going until we do the mod in January. Thanks again for the ideas!!