Got them chibaboom potential
Using power supply from unknown MIC source is always a risk. What about using the default power adapter from a "well known" precision weight machine with RS232 feedback?
A client call and told me one of the weighting machine failed to power up. I went there and took it back to my office. Open up the unit and saw this:
The power supply and charging board (lead acid battery) fried. Was wondering what the hell happened and why the PCB fired and destroyed the tracing as well, not a simple short circuit IMHO. Further investigation and finally discover the real culprit. The default 9v DC adapter some how short circuit and output 15V. Open up the unit and left speechless:
Incoming AC 230V feed directly into the transformer without going through a PP film capacitor. The output (measured AC 11v) feed into the 4 diode rectifier and filtered with a 470uf 15v capacitor, that's it. No output voltage regulator, zener diode etc...