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I'm trying to repair a charger for an electric drill battery. It has two SMPS inside. One large one that makes 12V to charge the battery, and another small one that powers a USB charging port and also a micro-controller that manages the charging of the battery. It's this second one that is not working, and I have no schematic for this charger. It seems to be a simple flyback design with feedback from an additional transformer winding rather than an opto-isolator.
There are two components that have me stumped, and that is why I'm posting. I hope someone can help me with information that would get to the datasheets on these components - especially the second one. I've searched both the part numbers and images to no avail.
One is a TO-92 that is wired like I would expect to see a MOSFET driver in the flyback circuit - except it measures as an NPN bipolar. I don't recognize the manufacturer mark, which looks like a D or maybe ID, and the model is 123S. That could be a MOSFET, (BSS123) but that one does not come in this package. It might also be a NPN bipolar, (2N4123) but that part only has 30V Vceo which looks wrong for this circuit.
The second one is even harder. It's a flat package with 4 leads, and the silkscreen is labeled U1. So this is some sort of 4 pin switching IC. It's wired just like I would expect, and it's electrically static (burned out?). Again, I've never seen the manufacturer mark, and I get nothing for part number TH608. Maybe it's something similar to the TNY268PN that effectively has 4 "leads?"
Thanks for any help you can provide.
There are two components that have me stumped, and that is why I'm posting. I hope someone can help me with information that would get to the datasheets on these components - especially the second one. I've searched both the part numbers and images to no avail.
One is a TO-92 that is wired like I would expect to see a MOSFET driver in the flyback circuit - except it measures as an NPN bipolar. I don't recognize the manufacturer mark, which looks like a D or maybe ID, and the model is 123S. That could be a MOSFET, (BSS123) but that one does not come in this package. It might also be a NPN bipolar, (2N4123) but that part only has 30V Vceo which looks wrong for this circuit.
The second one is even harder. It's a flat package with 4 leads, and the silkscreen is labeled U1. So this is some sort of 4 pin switching IC. It's wired just like I would expect, and it's electrically static (burned out?). Again, I've never seen the manufacturer mark, and I get nothing for part number TH608. Maybe it's something similar to the TNY268PN that effectively has 4 "leads?"
Thanks for any help you can provide.
