Lionel 12782 lift bridge won't lift

I also recently opened a lift bridge from when I bought it in 1992 and it works perfectly.  Obviously it should not stop.  If everything is truly level and plumb then I would check 2 things.

1.  Possibly one of the strings is off.   On the right side tower where the motor is, you can pull off the motor cover and see.  In the fully down position you should see no string wrapped around the main pulleys.  The end of the string will just be attached to them but completely unwound.  If you see string wound around them then somewhere along the line it jumped a pulley.  Just lift out the shaft with the 2 pulleys to disengage it from the motor, unwind the stings and replace.

2.  The other is the sensitivity needs to be adjusted.  That's in the control box and in the updated instructions.  I have never had to adjust it, but apparently Lionel put it in the instructions for a reason, so yours may need adjusting.

3.  However these 2 conditions should really not happen.  Most likely its binding somewhere.

I'm sure it you take your time you can find the issue.  These bridges do work very well once permanently mounted.

Update, after working with the bridge for almost 3 hours:

I removed the PCB's on top of both towers and realized there is only 1 motor.  I had assumed there was one on each tower.  I double checked all of the strings.  They are all properly on their pulleys.  Pappy, I used a level to check both towers.  Every way that I measure, the bubble is centered between the lines showing them to be true.

I am beginning to think that the strings running from the tower with the motor to other tower are just a little bit loose.  So, when it tries to raise the bridge, the far side droops a bit and then the bridge is not level.  So, it stops.  I will see if I can tighten up the strings a bit.

Sean, thank you so much for the updated instructions.   My bridge instructions must be the original one with no mention of the sensitivity control in the control box.  I had searched on Lionel's website and could not find any info for this bridge.  Do you have a link where I could download the full updated instructions?

Hi,

 Instructions attached below.  The symptom you describe about one side drooping is typical when the string on the main pulleys in the motor are not in sync.  What can happen is that if the bridge sticks for a moment (because it was not aligned correctly) the string will jump on one of the pulleys in the motor housing and now the 2 pulleys don't have the same amount of string on them.  So when it goes up, one side droops.

Very easy to fix.. Remove the motor cover (you have to move the circuit board out of the way, there is enough room I have done it) and you will see you can pull up the shaft out of the housing and then unwrap all the string from the 2 pulleys.  When you put the shaft back the bridge should now be at its bottom position.  Basically they should be completely unwound.

The instructions attached below have the restringing procedure, but don't make the mistake of trying to restring it.  The string lengths are set perfect from the factory and its actually high strength fishing string so they will last a long long time.  I'm thinking your 2 pulleys are out of sync with the amount of string on them. 

Here is a link also:

http://www.lionel.com/Customer...82&productNumber=

Thanks for the link and file, Sean.

I have had SUCCESS!!

I'm not sure exactly what I did...didn't follow the scientific method of only making one change at a time.

I rechecked that the towers were positioned properly and then lowered the sensitivity in the control box.  I guess I went a bit too far and the bridge stuck and the motor made horrible noises.

I removed the PCB and cover over the motor and verified that the strings were completed extended when the bridge was down.  While I had it open, I gave the gears a good dose of lubrication.  I was surprised that the original grease hadn't dried out.

I increased the sensitivity in the control box and gave another try.  I ran into problems and discovered that I had knocked one of the strings off the counterweight in the opposite tower.  The string was jammed and preventing the bridge from moving smoothly.   I got the string back on the pulley.  Gave it another try...and presto, it worked.  I've run it up and down 4 times with no problems.

Now it's time to permanently mount it on the layout.  I've done all my testing with it in the basic spot where it will be located....just have double check the position and drill the holes.

Thanks for your help, Sean.