I have been fighting this one for going on 3 months now. I hope someone has seen this before.

I have found the car in the pit with the doors wide open, 4' above the bottom floor, at 2nd and 3rd floor. It will run for about a week with no faults then go down with this string of motion faults, no drive faults and looking back through my notes it has always been going up. It will have a 121 *45 *25 18 then immediately after it will shut down on retries in search mode 431 *45 *25 18. The 2nd digit for the profile is not constant. I have replaced the car top encoder, the roller is plumb and tight to the rail, I've cleaned the rail and wheel. I've replaced the Zap board and both vane readers and re-grounded the whole car (the ground going to the car top had never been landed in the COP.) I have tuned up the velocity scaling and replaced every relay in the controller and the aux. contractor contacts. And no matter what I do I can't recreate it, not removing VC and letting it coast or opening the arm. loop. It's getting an MSU and NTS board in the morning and I have a car top encoder assembly on order for a very slight tick in the bearing.

Thanks for any help.

These are tough ones. I have fought the same ones and have made the same changes as you have. That said here are a couple that were successful for me that you can try. On one job I moved the Power to the Car top Encoder from the Zap Board to the MR Controller, as if it was a Governor Encoder. That eliminated the the 45 for that car. On another job, changing the Acel Decl time in the Drive took care of the 45 error. The car would occasionally overshoot the floor and throw a 45. If you have changed The acel/decel in the MSU you should look here 1st. also a flaky contact on the M Switch can throw a 45. Just a few more to try. Good Luck. AS a note all the 45's I encountered were on MODS

Thanks, I'll look at some of those. This is the original equipment in this building. A couple of strange things here, yesterday I was making the car drift, it got lost and searched down right on to the final, when I jumped SH to SH3 like I've done so many times before on these to get them out of the pit/overhead, the car drove down instead of up compressing the buffer and breaking traction. The mechanic that reset it yesterday found it about 3 inches off of the DSD switch, same faults, when he reset it it searched down and stopped then ran up and almost stalled at that same spot then took off.

this sure seems like a position encoder problem. when all else fails replace the relay pilot board.

Today I noticed a false start when the car was at the bottom floor with the doors already closed. It would only happen leaving the bottom floor and with the doors closed, if the call was placed before the doors closed it would take off normally. It looked like it was drifting or starting up then leveling back down to the floor but I found that the car was actually creeping down from the start, up relay picked and a negative VC. When it took off again it was normal and it would do this even with the doors inhibited. I replaced and set up the MSU board and it never did this again. I sure hope it is related to the faults that have been shutting the car down but this did not throw any faults.

When you get faults like this that don't make any sense, I tend to initially try to fix it with normal techniques, but it if that isn't working I tend to go to the main terminal strips and make sure that all my incoming wiring is tight on the screws or clamps. I have fixed many faults doing this.

did you replace any of the small relays on the main IO board? had something similar that lasted for 3 months, i also replaced many things, and could never recreate problem.
ended up replacing the UAX relay on the IO board, and it has never came back.

Every single one, and I have detailed the controller terminals twice. Last week I went through the drive terminals and found one terminal on the feedback resistor was not just loose but not tightened down at all. Before I even put a screw driver on it I noticed how far out that screw was. That wasn't the problem either.

Are you using a 14awg wire for ground?
Is the vane relay board being feed by a 28v center tap transformer?
Did you try reversing B+ and B- on the relay pilot board?

Yes, Yes, & No. If the encoder was reversed the car wouldn't run at all.

Are F4,5&6 fuse holder on the drive are making good contact?
What's your voltage for VC, +VPM, -VPM, TP10, MI+ & MI-?
What's the contract speed?
What's The car speed for up? Down?
What is the pulse value showing in the "DIST" screen after your floor runs?
What are your vanes spaced at?

Yes I have gone through ALL of this, the power supply voltages are solid. A month ago I set up the MSU and NTS board from scratch VC, VMP+/- and MI +/- are spot on, the up/down speeds are within 2 fpm of each other and contract speed (350.). I replaced the readers and set them exactly 12-7/8" to center, they run dead center of the holes in the vanes, guides are tight, built a new floor table at 30fpm and dialed in the heights.

After I saw the car creeping down yesterday I replaced the MSU board, and the NTS board because I had one. I set them up again and calibrated to the drive, everything is as close as I have ever had one of these. The issue I saw did go away, I just hope it is related to the shut downs.

Well my friend, it sounds like you put in one hell of an effort on this unit.

Keep us posted!

Well it's been running for 2 weeks since replacing the MSU. I'm not ready to say it's fixed, but it has been running for 2 weeks.

Lets pronounce this fixed. Good work.

Okay, 3 weeks today, it's fixed!
Thanks for all of your input.

Nice job, thanks for sharing...

Hopefully you got it. I can tell you of something else I have seen. The A-channel of the position encoder sends speed feedback to the Net Box. I had a noise problem in which the pulse width modulation of the door operator being used was being picked up by the ETS speed sensors. This was causing the 150 ft/min sensor to trip as the car got into the floor. I ended up rerouting the shielded pairs TC wires from the encoder and added ferrite beads around each pair.