Got it figured out. The FSM had the answer. It's a 5mm bolt on the spring part. I turned clockwise and voltage increased to the expected range (around 2.5V on min) and increased a little on the max heat (to about 0.9V) but remained in spec. I guess it just needs to be tightened a little after 25 years.

I used a 5mm socket with a long extension and a taped up swivel socket to make it more like a wobble socket. A long screwdriver helped me push the insulation up. I went through the antenna switch hole with the socket. This is different than the older version 1 setup described in the programma write up.

I took pics with my phone, but can never seem to be able to upload pics here.