partial_accumen

Much better pictures, thanks! I had suspected that both those ICs work together (and it looks like they do), but I couldn’t find any part that matches it in any searches. It could be a specialized ASIC they made, or they could have bought proprietary marked ICs specifically to prevent the kind of repairs you’re wanting to do.

Apologies I can’t help further, you may be stuck buying a new board. Maybe keep the dead one around in case you need a replacement part in the future.

For others looking at this, the damaged IC is silkscreened as IC7 (red square in my edit of OPs pic). OP, the fuse on this board is the green SMT device (that I put a green square around). Here’s the sales sheet for that fuse.

OP you gave a part number for the blown IC as HVS004, but from what little I can see in the picture I’m wondering if its something else. I’ve put a BLUE square around another IC8. I’m guessing thats in the same family, from where it is in the board. However, I can’t see what the part number is on that one. Can you share that one?

It didn’t occur to me that it could be part of the battery charging circuit, that would be nice as honestly I don’t care about using it as a battery charger (it takes two AA).

I’m a bit confused. Two AA batteries usually means 3v DC which is common to power a device. However, in your schematic on the left hand side, you have a symbol that represents a battery, its labeled 5v, and USB. I assumed this was the power source for the device. If not, why does your device have two power sources and one is not rechargeable.

I didn’t try image search, do you mean on Google Image Search?

yes

The photo isn’t great, but it looks like a 6-pin package. From your schematic I would assume its part of the battery charging circuit.

You say it “blew” is it shorted or open? If open, then my guess is the rest of the device should function, you just won’t be able to charge the battery. If its shorted, I could see that draining any current away from your piezo driver.

For component identification, have you tried an image search of your board (with a better picture with more light)?

Full disclosure, I’m not an expert on this equipment, but some insight I can provide might be better than nothing if you get no other answer posts.

I don’t know this hardware, but interfaces very often have some kind of buffer circuitry right before the connector that leaves the unit that doesn’t change the logical signals but provides either circuit protection to the model or signal stabilization. If you’re not getting any variable signal (and just getting that standing 8v out) then this is where I’d look first.

If I deciphered you “2nd white plug port” then its this photo, and the circuitry I’m talking about I’ve circled in blue:

This looks like what I’d expect to see. The larger black cubes are inductors (coils). I can’t see the number to know what those 8 pin SMT ICs are next to each inductor, but there’s an orange capacitor and series of smaller inductors next to each. This feels like signal buffering stuff. If your surge came in through that connector, then this would be the part of the board damaged and where I’d start the search. The good news is, that buffering logic is pretty simple. It doesn’t “create” it likely just “stabilizes” or “cleans up” what the rest of the module creates.

As a technician, I’d get the pinouts of those 8 pin ICs, identified the input to each, and put my oscilloscope leads on those input pins. If you’re seeing good signals (not a standing 8v signal) then you know the rest of the upstream logic is good, and you just have to replace some cheap front end buffering components.