My LOTR started to reset its memory and display "open the door" when I power it up. It does not happen every time. It has never reset while the game is powered up. Running code 10.0. I have verified I am getting 4.7V between Vbatt and GND when powered off so its not the batteries. I am going to try pulling, cleaning and reseating the PAL and CPU chips. Any other suggestions?

I cleaned and reseated the PAL and CPU. To test if it fixed I would power on once a day. I did this for 6 days, just a quick power cycle to see if "open the door" came back. It did not so on day 7 I started playing again (~2hrs of play). Next day I turn game on and "open the door" is back. Could be coincidence but seems like problem may only occur after board warms up. So it could be a solder, connector or socket issue, or could still be a bad PAL chip like the other post suggests. I think my next step will be to replace the PAL.

Before swapping the PAL chip I called my local pinball repair shop, Firebird Pinball. They recommend that before I swap any chips I should try replacing the battery holder. I swapped in a new holder a little over a week ago and have been testing the machine daily. It appears this has fixed the issue! Thanks for the great advice Firebird!!!