Okay, so here’s how my whole MOSFET swap mess went down. I had this old pedalboard power supply project gathering dust in the garage – classic “I’ll finish it later” situation. Finally dug it out last week, fired up the circuit, and bam. Dead. Traced it back to that tiny BS170 FET acting like a brick wall. Zero flow.
The Replacement Hunt Begins
First stop was my usual online supplier. Typed in BS170 like I always do, ready to hit “Buy 10.” But nah. Backorder notice. Checked three other sites – same story. Either out of stock or crazy expensive for what it is. Felt like hunting for unicorns. Annoying, right? So I mumbled, “Screw it, gotta find something else that’ll work.”
Digging Through the Junk Drawer (Literally)
Started pulling open every plastic bin labeled “Electronics Misc.” We all have that graveyard of parts. Found a bunch of FETs in antistatic foam – 2N7000s, IRF510s, even some IRLZ34Ns. But specs? Nah, half the labels faded or missing. Googled datasheets like a madman comparing numbers:
- Voltage rating: Needed at least 60V.
- Current handling: Pedal draws under 500mA.
- Gate Threshold: Had to play nice with 5V logic.
Felt like doing homework instead of fixing stuff.
Bench Testing Chaos
Grabbed the three closest suspects: a 2N7000 (classic), a ZVP2106A (random find), and a BS250 (weird P-channel, but gave it a shot). Hooked ’em up one by one to a breadboard with a dummy load resistor and my power supply.
Trial 1: The 2N7000
Powered on… and smoke. Not the good kind. Fried immediately. That “60V” rating lied hard. Cheap junk.
Trial 2: The BS250
Wired it backwards because P-channel. Duh. Fixed that… and it barely switched. Like pushing a car uphill. Useless.
Trial 3: ZVP2106A
This one surprised me. Handled 60V no sweat. Gate clicked on at 3V cleanly. No magic smoke. Measured voltage drop across load – almost identical to the dead BS170. Eyebrow raised.
The Real World Shakedown
Couldn’t trust the bench test alone. Soldered the ZVP2106A into the actual pedal supply circuit. Plugged in a distortion pedal, then a delay. Voltage stayed rock steady. Felt the FET – lukewarm, no panic heat. Left it cooking for an hour. Still alive. Did a happy-dance-wiggle at the workbench.
The Verdict (For Now)
So yeah, the ZVP2106A saved my dumb project. Is it the perfect BS170 twin? Nah. Slightly higher gate capacitance, but the pedals didn’t care. Moral? When your “go-to” part ghosts you, dig deeper. Sometimes the random thing in your bin just works. And now my doom-metal riffs stay powered. Win.