Hello, I am The Doctor, from the planet Gallifrey. I have a Casio Prism and it's power regulator is dead. I was recently at the Cemtech Makerfaire booth and I was told to check it. Yup, the IC is bubbled and fried. Anyway, because the chip is fried, can someone tell me what chip it is. I am planning on replacing it.
Can someone check their CG10 and tell me what the chip number is... Pretty Please...
Markings on the chip are unlikely to be useful, since SOT-23 devices rarely have actual part numbers printed on them, nor manufacturer stamps to aid identification.
The circuit around that looks like a switching power supply, so I'd guess that damaged-looking device is a N-channel FET of some sort. Hard to say beyond that without probing a live circuit though.
Hmm... OK, that's a start. I guess I'll have to find other people who've tried to fix this issue and ask them what chip it is. (P.S. I Miss my calculator
)
By the way, I visually inspected this calculator at Maker Faire, and I wasn't convinced that this component was damaged. There did appear to be some surface cruft on the package, but I didn't see any charring or bubbling myself. I certainly believe the OP that he saw it, though.
Hard to tell from the photo, but I'm inclined to agree with your thought. I'd expect damage to the package to be centered (where the die should be), but what look like scuffs on it in the photo seem to be on the right side and a smaller section on the bottom.
Well, upon closer inspection, the chip did seem to just be dirty, but I can still smell fried electronic inside, so, what else could it be?
The obvious culprit would be a capacitor. The big orange (tantalum?) ones are probably okay, I wouldn't expect them to have a "soft"
failure mode like I know electrolytics tend to have.
Personal experience says failing electrolytic capacitors can smell unpleasant, so I'd look at the big electrolytic caps (the blue ones mounted sideways, C307 and C308).
The caps seem to be ok, how could I go about testing them?
So I followed gbl08ma's post and here's the chip
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