I tried a regulated power supply today on my Lynx II - same issue initially, blinking red light. I was doing some continuity tests on D9, D10, and D11 and it started to smoke from the board. Couldn't pinpoint from where exactly, but it was from around the mosfet or diodes. I tried powering on again later and it started up (screen was completely dead though). I was getting 5.1V across D11 and C35. It was also 5.1V across C40, C41, C44, and R75. Zener diode orientation had the stripe towards R74 as per the instructions.