I would like to thank you for all your words of wisdom and technical expertise. I really couldn't have done any of this without some help.
So today, this is the latest--the power supply is up and running again after about 1.5 months or troubleshooting, diagnosing and test every active component within it!
What finally came down as how come the pico fuses were blowing and even before that with the original In-rush resistor in place was overall the diode! I had an NTE equivalent replace diode I bought for the ERB2406C (obsolete) and figure for fun, let's see what happens, seeing all electrolytic capacitors checked OK, bridges, and transformers were fine, this was the only device I didn't replace, seeing my ohmmeter readings were showing that it was less resistance forward biased and high resistance reversed, so didn't pay too much attention to it there. So I just soldered out the old, put in the new an immediately the load on the 12 volts illuminated! The PWM controls ultimately works as expected and it did begin to regulate! Five volt regulation came about too with the correct pass through transistor, and everything was fine on that end.
I am really ecstatic that this all worked out as it did--the next option was tossing it in the garbage or broke surplus on eBay. At least now there will be a machine that can use this some kind of 8-bit fun can be had.