Sometimes, I will cut a couple windings off the return spring to make it pull a little harder and get past the 9 to the 0 position. They also seem to get better about this after some play time.

I suppose the contacts could be the issue but They would really have to be tight- if your not seeing that I would look elsewhere- I dont recall this being quite that sensitive an adjustment in my rebuilds of Gottlieb score reels. Are you sure the actual mechanism is working perfectly from a pure mechanical sense? I would very carefully inspect the reel in question and compare it to another identical functioning version. Sometimes subtle issues add up.

I know that I may get some feed back on this (some will say no oil), but some times after cleaning I have had to go back on ones like this and take them back apart and add a dot of oil in places. I always will pull the coil plunger in with my finger and make sure they are crisp and snappy (fire them with my finger all the way threw 0 to 9 and back to 0) and if I have the issue you are describing after rechecking everything I have had a few I have disassembled and added that dot of oil and all is good.

Is it cycling through and continually firing the coil to try to reset- just not sure i fully understand exactly what is happening. I get that a score reel is not resetting to zero- is it a decagon reel? Does the cycling from the score motor continue until it fixes? Seems like maybe its not a decagon and the reset finishes "normally" but is not complete?

What position is the reel- a ten? Hundred?

Most likely the 9 position switch has to much ‘throw’. You need to carefully adjust it so there is less tension. I don’t remember if this reel has the ‘2 into 1’ blade, but if so it needs to be adjusted evenly. A bit tricky if so. Make sure you bend the blade from the very bottom closest to the switch stack. Hope that helps.

Compare the reel that's not working to another that is. Watch the contact switches. More than likely it's the 9 position switch (outer most switch) that's too tight. Adjust both blades so that they still close when in the 9 position. Comparing to the other reel can help. There's really no trick to this other than a little trial and error. Good luck!

Are these decagon reels? If so, there is a metal arm that rides the inside of the wheel that moves at the 0, 1-8 and 9 positions. It's what moves the switches. We had a problem with one reel and it ended up being that the metal was bent a bit at some point and caused too much tension on the wheel. Had to bend it back a bit then adjust the switches but it's all good now!

Before bending it, we cleaned the entire unit and adjusted all switches but it still caused trouble. Bending the metal wire piece a but was the only thing to fix it. It took a few tries to bend it properly as well

MY TA 1000's reels 9th pos switches are a total finicky pita! Lucky it's a fun machine.

Thanks for the update!
Glad you got them going, and they usually keep working if you play regularly. perhaps improving...

This is almost always caused by too much tension on the 9 position switch. The switch puts too much pressure on the wireform that moves it, and the other end of the wireform rides on the reel itself, which causes the reel to hang between 8 and 9. Cutting off springs generally is not a good solution for this problem, just careful adjustment of the 9 position switch so it still closes, but doesn't put so much tension on the wireform.

i agree, when this happens 9 times out of 10 it is the blade tension on the 9th position. if that blade is adjust out a bit to relieve the tension it will work just fine without cutting springs or altering the spring washer and no grease/oil needed.
the one time out of ten it doesn't work it is cause by harden grease on the reel and it needs to be taken apart and cleaned.

I have found this to be common with Gottliebs, take 3 coils off and a touch of lube on the reel cam and it is a new machine.

Very common issue on Gottliebs. I don't like hacking springs by cutting off coils. Clean everything and adust the switch stacks, and good to go!

Springs do lose tension due to use or heat, you could replace them if a concern. You have nothing to lose cutting coils off.

Scoring reel springs see an incredible amount of cycles, every time they are stretched and released they lose an almost infinitesimal amount of strength. This is well documented in automotive circles be it valve springs or leaf springs.