The 1/4 way up could be a traveling cable issue. Just my thought.

if it happens only in the up direction, it must be getting getting lost. almost has to be one of the rail switches in the wrong state intermittently.

Is it possibly tripping the low oil timer?

Is the cab apron clipping the first floor door pickup assembly as the car passes by?

one more thought, what is dropping the up starter out. possible bad contact on a clc board relay, or a loose connection on something. jeez, so many possibilities. good luck.

check spring steel on the limits, they get weak and give intermittent troubles.

Not sure but try rac66, it sounds like the hold torque setting on the door operator is relaxing and the clutch is barely clipping the pickup assembly and breaking the hall door contacts as it leaves the floor. I'm assuming a bunch here, though.

Trying to give you ideas. Remember, it is always the simple stuff that gets you.

slow down input occurring at the wrong time. hmmm. you have the tool, how about a new hoistway scan? have you tugged on the limit switch connections? some are notorious for breaking right at the crimp point (TSL is famous for this). Or, where the wires are fed through the switch base into the unistrut stick, found breaks there too. Boa makes a good point also. Hey, I've seen one where with the switch cover on...contact trouble. Cover off...no trouble...go figure.

slow down to early, thats correct, did a new hoist way scan just to eliminate that to no avail. switches meter fine, wiring is fine, took a couple day break to catch up on other down cars, going back tomorrow to continue. maybe boa is on to something, maybe the uts switch is weak, and breaking. i did check the locks, etc. no problems there. will probably end up replacing the switches just need to get them ordered. will keep you posted

Very easy to check. By hand push the roller, if tension is off at all, the spring steel is getting weak and probably about to break. I've ordered just the springs before, I think from PSI

well went back today, did not have switches so i decided to experiment, i jumped the uts and tsl switches to eliminate switches, problem still occurred. pulled the switch tree off, and went thru all switches and wiring no problems found, put back and problem still occurred, installed new sensor card, same thing. now starting to get frustrated, when it does fail, i can here the car floor passing gong come on just as the car leaves, so I'm thinking to myself, it seems like the selector actually thinks it is further then it is, like it is counting to quickly. so i decide to recheck the first floor level magnet, and parity magnet for the umpteenth time. this time i flip both magnets upside down from there original position, realign again, and put back in service ran the car continually for nearly 3 hours and now the car will not fail. now I'm thinking the elevator gods are screwing with me, it just can't be, the car is going to fail, but it is still running. packed up my tools, left with my tail between my arse, feeling a few years older, and not very much wiser. will keep you posted

Well Vatorgator,
It's odd to hear that flipping the magnets was the solution to the trouble you have experienced. But there is no need to beat yourself up. You stuck with the job and applied the skills you've developed over your career. Anyone that has read your post or has reached out to you for help knows you should hold your head up.

My mistake, I did not pay attention. I assumed being a 2 stop it was a DMC 1A, the other limits can fail also but I've only had the springs go on the floor switches.

good to hear! in a few days you won't remember it.