Yes, I have still been working on this, but it's been cold here and the lab is in the garage which is a pain to get up to acceptable working temp w/ my kerosene heater. Also, I have been rebuilding stuck my laptop.
I would have to remove the RF box to gain access to it (cover is on the PCB side). I did try pin 3 of the RF-PCB connection to the composite video input of my PVM directly and only had brief interference show up from actual touching of the signal pin. PVM does not indicate lock of signal of any type. This is w/ and w/o cart. I also measured freq. of pin 3 and it varied between ~12.5kHz - ~13.5kHz.
I'll have to take pics of the reworked components and post. I do believe you guys are correct about Q4 and even the resistor on the RAM chip (didn't look like a rework to me, I was just curious on that one). There are a few components that have been reworked, however.
Thank you,
-Allen