gazownik
Newbie level 4
Hi there,
what I have here is a cheap 3-12V power supply, probably something resembling the one below:
more detailed pictures here:
The problem with it is that it's completely dead. I disassembled it and checked electrical connections with a voltmeter set to "beep" (diode test). The rectifier diodes seem to be fine (at least the multimeter is indicating "something", same goes for 230V leads and primary and secondary windings of the transformer (beeps on their respective sides). Input zener diode seems to be dead but I suppose it's parallel so it shouldn't be that much of a problem. Fuse is also ok, i.e. beeps. I also checked the transistor (marked with red ellipse) attached to the radiator using beeper (although I'm not sure if it's a viable method to do that) - putting one probe to the middle lead and checking junctions by putting the other to the remaining two. It also indicates semiconductor junction inside. I'm out of ideas - what should I check next? Any ideas?
Thanks in advance.
what I have here is a cheap 3-12V power supply, probably something resembling the one below:
more detailed pictures here:
The problem with it is that it's completely dead. I disassembled it and checked electrical connections with a voltmeter set to "beep" (diode test). The rectifier diodes seem to be fine (at least the multimeter is indicating "something", same goes for 230V leads and primary and secondary windings of the transformer (beeps on their respective sides). Input zener diode seems to be dead but I suppose it's parallel so it shouldn't be that much of a problem. Fuse is also ok, i.e. beeps. I also checked the transistor (marked with red ellipse) attached to the radiator using beeper (although I'm not sure if it's a viable method to do that) - putting one probe to the middle lead and checking junctions by putting the other to the remaining two. It also indicates semiconductor junction inside. I'm out of ideas - what should I check next? Any ideas?
Thanks in advance.