Sochi Tech, 79xx regulator can't reach -12V as specified

I can't open the link in post #8, but based on the picture in post #1, FWIU, this discrete component voltage regulator module can be used as an LT337. Simply connect like a 79xx and adjust the trimpot in the module to achieve the desired output voltage.
Screenshot 2025-05-19 at 17-07-12 LM7912-connection-diagram.jpg (JPEG Image 362 × 264 pixels).png