Surf pi 1.2 troubleshooting

[Boe]

Hello!

I recently bought the surf pi 1.2 kit on silverdog. I soldered the components to the circuit board and made a small test coil with a few rounds of wire. Then I hoocked it up with a 12vdc ac adapter.

I get the coil to react to the metal, but the electrolytic capacitor is making "buzzing" sounds and gets very hot when the coil is connected. The irf9640 transistor also gets hot. (with coil)
I've only tried it with the power on short cycles in danger of ruin components.

Hope someone can give me some feedback. Sorry for my bad english

[Boe]

Okay...The capacitor is not getting THAT hot, only the transistor. (I suppose it should be slightly warm?) But it's a little strange that it comes a small buzz sound from the big
electrolytic capacitor? (Also with the speaker disconected)

I just have the basic soldering skills, and sucking on electronics.

[Tepco]

First construct proper coil, 250-400uH inductance. Operating with coil consisting of only few turns will generate very high peak current during pulse, producing symptoms you described. This can damage components. AC adapter can be used for tests, but to get full performance, use battery (and test outdoor if possible). Be careful with adapter (output voltage and variation under load), over 15V can damage components too.

[Boe]

thank you for reply Will try to make proper coil and get some batteries

[6666]

Can you show a picture of the electrolytic capacitor that is making "buzzing" sounds and gets very hot and how its connected to pcb ?

[Qiaozhi]

Okay...The capacitor is not getting THAT hot, only the transistor. (I suppose it should be slightly warm?) But it's a little strange that it comes a small buzz sound from the big
electrolytic capacitor? (Also with the speaker disconected)

I just have the basic soldering skills, and sucking on electronics.

Unless you have a powerful bench supply, it's probably not incapable of supplying enough current. A coil with too low an inductance may damage the mosfet. Do you have the electrolytic fitted with the correct polarity?

[Boe]

The symptoms disappeared when I tested a coil with more turns