My cell phone cig lighter charger let the smoke out. The plastic sleeve around the inductor was fried, so I pulled it out and it measured 4.1 uH; whether that's correct or whether it has shorteed turns, I don't know.
The Q1 high current PNP or P-Ch FET case split open, and it and the inductor got so hot that it melted the solder and discolored the PC board. But I don't think the traces are damaged. BTW, it's all thru hole parts. :-)
My main problem is that I can't read the part number on the Q1. It's a TO-92 case, and looks like it would be a PNP Japanese type transistor because the pinout is EBC (or the equivalent SDG in a FET). I presumed this because the other two transistors are Japanese, as marked below in the schematic. The unit is marked made in China. The only things I can read on the face of the transistor case is an HE on the upper right, and a C below that on the lower right.
I believe it failed bacause the lousily soldered wires were so very close to shorting, but not touching the traces that it passed testing, but then shorted and failed later. I got some pics, and I may post them to ABSE. I looked at Sam's repair info here but couldn't find anything about the SMPS or any transistors.
The cig lighter plug case popped apart easily, so if you have one and a minute, find out what the part number is and post it for us all. I got to d/l and try out the Andy's schematic prog, and I entered the schem, but I'm not sure about the value of the 100k 1%. It seems too high, so I might be reading the bands backwards. Thanks.
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Cell Phone Charger by Watson A.Name Aug 30, 03 Down converts 12V auto cigarette lighter to the cell phone battery voltage.
o------+--------+---------------------+ Q1 TO-92 + IN | | | PNP HI CURR ?? | | Q2 2SA733 | or P-Ch FET ?? +------+ |< |< (totally fried) | +-----| +-----------| | | |\ | |\ | .-. | | | 4.1 uH | 2K | | +-------+ | ___ | 1/8W| | | +------------+--------UUU-------+---o | '-' .-. | 1N | | + OUT .-. | | |1.8k | 5819 - +--------+---+ RED | | | | |1/2W | Scho ^ | | | | |3.3k | '-' --- ttky | | -. | + '-' | | --- 470 == | 560 | | ### | | === | pF Cer GND | ohm | | -+- | LED | GND | | '-' | 100 uF V --> +----------------+ | | | 16V - --> | 560 100k 1/8W| +---+ | | ohm ___ 1% | === === | +---|___|--+---|___|---+ GND GND | | | + | | ### 10 uF +----------+----o \| | --- | | - OUT Q3 2SA945 +--+-------+ | | 1.5 .-. BLK