PA? Sorry not familiar with that abbreviation. Got a part number or picture?

6300PA6 door board. They’ve used it for years but obsolete now

Yes! have the same dilemma currently on a TAC20 (6300PA3). TK still makes the boards but there is a world-wide chip storage, so any boards they do have they are not selling to outsiders. you can try to get board repaired but the success rate is only 50-60%. i think the LD-16 drive kit upgrade is the way to go here depending on controller. at least you can buy parts from Wittur or Kone..

Keep in mind that you’ll still have to get the 2 boards from TK. The CAN interface board and the main board because it has firmware in it you can’t get from Wittur to be code compliant.
Going to an MOVFR or MOVFE isn’t a bad option if you have an open discrete port and at least 6 spare travel cable wires.

Here is the chart for door boards , Vertical Express sent this

I think the LD-16 (Wittur product is your best bet as they are engineered specifically as direct replacements for the old Miami Elevator/Early TK door equipment. I'm also a grinch of harmonic operators. They are just too outdated and have too many moving parts. If you wanna go cheaper, GAL has a direct replacement linear product where the only thing you'll need to replace is the operator itself. You will be able to reuse other existing components, such as the skate and hanger roller/tracks. It's called OMNI. Just like LD-16, there's no limit cams/switches to deal with. If you've been having difficulties getting parts from VE/TKE, the GAL product is your best bet. It might be easier to source parts.

LInk: https://www.gal.com/wp-content/uploads/2023/08/GAL-MONXT-OMNI-Telescopic-Linear-Operator.pdf

You could also get a Glide-A (or P) from Otis.