I’m building my PSU using the AI Synthesis PCB. I’m running into a problem where I’m getting no output from the L7912, and I’m not sure how to fix it. Forgive my redundant language below. I just want to make sure I’m doing the measurements correctly as well.
I’ve tried with two different L7912s now. The voltage regulator is definitely the correct one, it’s definitely in the right way. However, when holding the red lead to the output of the L7912, and the black lead to the ground rail (from the 2*5 pin connector output), I get 0.
To be honest, I’m not even sure that I’m testing it correctly, just trying to watch youtube videos and read about it on forums… but when applying the red lead to the positive voltage and the black lead to ground, I’m getting 25.8v. This is also what I get when testing the L7812. Then when testing the red lead to ground and the black lead to negative voltage, I get 25.3v.
as you can tell, I have a lot to learn. Any help at all is appreciated, thank you!
You must be making a mistake in your measurements; assuming your wall wart is 12 VAC, then there’s no way you can get 25 VDC from anything to ground. Please either describe in detail or post pictures of where and how you are doing your voltage measurements.
Thanks, attached are images of how I’m measuring. Also pics of the wall wart.
please note how messy it looks and how I’m using serial resistors to get 2.4k ohm each. I also replaced these prior to discovering the voltage regulator issue and ruled them out. while that could still be the issue, they are not shorting anything wild as they may appear, I’ve made sure.
also the 3300uf caps are too big for the pcb so I had to sort of leave them loose, and twist them a little bit, bit they’re all in the right direction and they’re not shorting beneath.
the picture with the measurements indicate the pins I tested and with which leads.
I would just like to say that this was a very satisfying thread to read…
I wish that all of my build fails had been due to ‘on the wrong mode’ and also that my build fails that were ‘one the wrong mode’ had been solved before desoldering everything and cursing …
Glad to say that I found this thread as I was having exactly the same issue with a self built power supply from frequency central, I was ready to throw it in the bin. I had changed the power regulators, checked the AC wall wall wart for correct voltage… then thought, one last go, someone else must have come across the same problem. and here I am what a dunderhead I am !
what a dunderhead I am !