Enrico

I've built one too. But since i discovered Hydrogen Peroxide + Muriatic Acid, i just don't use it anymore. You can find (at least here in italy) Hydrogen Peroxide 40% vol from airdressers, it is present in the products they use to make air shiny blonde. I just lay the pcb in the plastic box and cover it with a small amount of muriatic acid (just enough to cover the pcb), then i squirt a small amount of air product and wait around 10 minutes, less if you give it a little shake sometimes. I agree that this solution is far more dangerous than using ferric cloride, but if the right precautions

Thank you ;)

During the process of building my own dual-variable power supply, I decided to mount a cooling fan, controlled by a lm35 temperature sensor, to cool off the heat produced by the numerous of components. Inside my box (old ammo case from WW2) there is very little space: - 2 backlit displays (2x16 char) - 1 Toroidal transformer 50 VA - 1 Toroidal transformer 225 VA - A total of 4 "TO220" voltage regulators (2x 7805, 1x 7905, 1x 7812) each one with it's fellow heatsink. - A big heatsink where 2 LM338TK (TO3) are mounted, this heatsink is mounted partly inside the case, partly outside. I placed