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| Console repair: Help identifying components |
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| newtekuser:
Have a portable gaming console than doesn't power up (power LED stays red when charging and only blinks red once when pushing the power button), upon disassembling it I see what appears to be a blown 0603 component. From what I can tell, it is part of a power regulation circuit. It doesn't appear to be a diode because when I measure the other two identical components next to it there's no voltage flowing through them. None of the components in this area are shorted to ground and when I measure the other two identical components similar to the burnt black one I get about 0.40 ohm. This tells me this may be a current sense resistor. I'm guessing this component was blown by the in-rush current from the wifi chip which is in the biggest component in the area. I also don't see any diodes around which is very weird. As part of the same power regulation circuit I also see three mosfets marked "AHRP 590" but a Google search doesn't reveal anything of use about them. I'd like to see if any were taken down with the blown component if I can find any data sheets for them. In the two pictures you can see the board before and after cleaning. Can someone confirm if this is indeed a current sense resistor? What about the mosfet? |
| fzabkar:
The manufacturer of AHRP is Monolithic Power. Edit: MP8765GQ, Monolithic Power, 24V, 6A High Efficiency Synchronous Step-down Converter with Hiccup OCP, PWM/PFM mode pin and output discharge, marking AHRX+XXX, QFN3x3-16P: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP8765/ http://markingcodes.com/search/c/ahr Edit #2: Could the "current sense resistor" be a ferrite bead? |
| newtekuser:
--- Quote from: fzabkar on July 12, 2024, 06:25:03 pm ---The manufacturer of AHRP is Monolithic Power. Edit: MP8765GQ, Monolithic Power, 24V, 6A High Efficiency Synchronous Step-down Converter with Hiccup OCP, PWM/PFM mode pin and output discharge, marking AHRX+XXX, QFN3x3-16P: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP8765/ http://markingcodes.com/search/c/ahr Edit #2: Could the "current sense resistor" be a ferrite bead? --- End quote --- Thank you for the link! I went with my gut feeling and ordered some current sense resistors since I could not find ferrite beads of the same resistance. I also ordered a few of the MP8765 buck converter ICs just in case since they're cheap. |
| fzabkar:
I would make sure that the load side of the DC-DC converter is not shorted or overloaded. |
| wraper:
Blown component is a ferrite bead. Exact value not important, what matters the most is if it can handle enough current. FWIW you can replace it with a jumper and circuit will work just fine. Although I doubt it blew by itself, something else should have failed and caused a very large current flow. You should check if either side of the ferrite bead is shorted to GND. |
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