Dashboard Clock goes off?

[TeeThree]

Thanks for the feedback Sven. I'm confident you may have found a lasting solution to the problem. I will look into the DC-DC converter - a nice neat solution.
Would something like the old LM317 work as well? I already have that in my box of spare parts.
If i set the LM317 to 1.5v this should be ok from what you have discovered from measurements.
Thank you for your effort and feedback.

[sven337]

Originally Posted by TeeThree

Would something like the old LM317 work as well? I already have that in my box of spare parts.
If i set the LM317 to 1.5v this should be ok from what you have discovered from measurements.

Electrically it will work. Thermally I'm not so sure. LM317 is a linear regulator so in order to deliver 300mA@1.5V it will draw 300mA@12V and dissipate the difference, which is 3.1W.
The TO220 LM317 datasheet mentions a thermal resistance of about 40°C/W, so you're looking at 120°C over ambient temperature for a device with a maximum operating temperature of 125°C. That's why the original board had 6 transistors...
I wouldn't attempt it. A buck regulator has a better efficiency.
The LM317 is supposed to have thermal protection so it will likely shut down without burning too many things, but if your board is like mine any heat is too much heat.