RD-6D2-A Circuit Board - Both Sides
I've flipped the lower photo around (backward) so the orientation of the parts match the pattern in the upper photo. I know it looks weird, but thought this would make viewing easier.
Although the image is reversed, you are looking at a design here that is basically the circuitry of the TR-66, the successor to the TR-6. It appears that the last few TR-6's built after the TR-66 went into production used the same circuitry as the newer model. In fact, my yellow & red TR-66 has the revision R-6D1-A circuit board in it.
If you just can't get enough and wish to see an image that shows the parts side laid over the printed pattern, click here.