Cadet IV Ramps uncommon component substitutions

Hello all,

When I finally got around to building my Cadet IV Ramps yesterday I realised there were some slightly less common components that I didn’t have in my component drawers: the 15uF MLCC (ceramic) capacitor and the BS170 MOSFET transistors.

For the 15uF I substituted two 33uF electrolytic in series (call them capacitor A and capacitor B). Solder the - leg of capacitor A to the + pin of the capacitor B. On the PCB use a multimeter to identify which pin of C18 is connected to ground, and solder this to the - pin on capacitor B. Solder the other leg of C18 to the + pin of capacitor A. This gives a value of 16.5uF, which is near enough and I had no problem calibrating it.

For the two BS170 the 2N7000 is a suitable substitute so long as the current requirements are below 200mA (the BS170 is good up to 500mA), which I’m quite sure it would be. The pinout is reversed on the 2N7000, so they have to be installed backwards compared to the silkscreen.



For the 15uF cap, this Mouser part should work: