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I have an HP Folio 13 laptop. While plugging in an external SSD drive I managed to blow up the drive, and at the same time damage 1 laptop USB port. There is the "burnt electronics" smell in the vicinity - although not so much in the laptop.

I tried turning the laptop off overnight (and disconnecting all peripherals but not the built in battery), and that did not fix it, so I'm guessing if there is a fuse its not a re-settable one.

I opened the laptop and identified the USB port (along with an audio jack) are on their own board (HP part number 672358-001) which is attached by a cable and looks relatively easily replaceable, albeit not particularly cheaply.

There are a number of (what look like) surface mount transistors on the front of the board and, on close inspection some things which I am guessing are SMT resistors and caps as well.

here are pics of the front

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and rear

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of the board.

Does anyone know how likely the blown bits are on this daughter board (rather then on the main board), i.e. how likely is it that replacing this board will fix the USB port ?

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  • There is only one Transistor, based on the labels. Q1 means Transistor 1. D1,D2, etc mean diode 1, 2, etc. Multi-diode packages. Since it looks like a simple two sided board, draw a schematic, and then use a multimeter to test all the parts. If they all work as they should, then its likely to be on the main board. If you trace the usb pins to the connector, see if it goes directly or to other parts. But the board only costs 20 bucks or so from a quick google.
    – cde
    Jun 25, 2014 at 1:58

2 Answers 2

Reset to default
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It's hard to work out from the photos but I'd say L1 and C6 are forming an LC filter on the supply for the USB port. The relatively large value of C6 probably also serves as a reservoir cap to help handle voltage drop caused by short current peaks over the fairly thin cable. You could rule out problems with those components by measuring that you have 5V on the USB connector with a multimeter or otherwise connecting a device such as a phone that will attempt charging if USB enumeration doesn't complete.

D1 may be a clamp diode, I'd expect a pair of them for protecting D+ / D- but it might be some sort of power supply clamp. Depending on how experimental you're feeling you could try removing it in case it failed shorted. It could leave the motherboard open to damage though from external sources of over-voltage / ESD spikes etc.

All the components on the lower side of the PCB appear to route to the audio connector, so I doubt if they have anything to do with it. In general looking at the PCB most of the main USB interface must be on the motherboard, so I'd say it's likely if you're getting power out of the USB port the problem is more likely to be on the motherboard. If not the problem could still be on the motherboard but you'd really need to trace back the connections and see if you're getting any power on VUSB without this board attached.

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  • Thank you for your very complete answer. I'm going to order a replacement board and I'll put feedback as to whether it works here. From what you have said in paragraph 2, I think its quite likely that D1 has failed.
    – davidgo
    Jun 25, 2014 at 19:00
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I replaced this USB PCB and unfortunately the problem persists. Hopefully I'm not doing them a disservice, but it seems to me that HP have not followed best practices here, and do not have resettable fuses or similar, so I'm still down 1 USB port (out of 2).

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