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kounishin · 10-31-2017, 11:54 PM

This is going to get a bit detailed. Sorry about that, but it was a pain in the rear to dig up some of the information (like the USB IDs), so if I put it here hopefully it'll be easier for other people searching to find with some context, rather than a German forum thread...

In my particular case, the PMU chip still gets hot whenever the Kobo is connected to power - whether the power LED has been turned on or not, whether the battery is connected or not. I agree that this probably means the PMU is faulty, which is a pain; replacement batteries are easy enough, but fixing the PMU would probably require a new motherboard.

I don't know what would happen to a healthy Glo HD with the battery disconnected, of course. I have seen a couple of reports which suggest that the same thing can happen with a fully drained battery, and in that case it'll fix itself if the battery can pick up a charge again, but that's just anecdotal. In my case there's some slight distortion visible on the PMU (not actual melting or discoloring, but with light at the right angle you can see the difference in what looks like a heat spot; there's what looks like a small dent in the back cover at the same spot), so I'm betting that the PMU chip is toast.

Diagnosis notes:

while the Kobo draws power (and gets hot) whether it's turned on or not, it will only show up as a connected USB device when turned on
on Windows, you'll only get the "SE Blank MEGREZ" notification the first time you connect it (when Windows is setting it up as a new device)
it will still be there on subsequent connections, but it doesn't show up in Device Manager as anything distinctive: just a generic USB HID device
you can identify it with something like USBDeView (where "SE Blank MEGREZ" will show up in the Device Name column), or if necessary you can look for the device with vendor ID 0x15a2 and product ID 0x0063
it may or may not be easier to identify on other OSes; I haven't checked them, because I'm lazy

Come to think of it, I didn't actually confirm whether it still behaves the same way with the memory card removed; I'll check when I get the chance. Based on the other reports (covering a bunch of different devices, not just Kobos), though, I'm pretty sure this mode is built in to the FreeScale SoC and so it'll only happen when no other OS is running, whether that's because of a faulty SD card, a blank one, or the lack of one entirely.

10-31-2017, 11:54 PM	#138
kounishin Junior Member Posts: 6 Karma: 10 Join Date: Oct 2017 Device: Kobo Glo HD	This is going to get a bit detailed. Sorry about that, but it was a pain in the rear to dig up some of the information (like the USB IDs), so if I put it here hopefully it'll be easier for other people searching to find with some context, rather than a German forum thread... In my particular case, the PMU chip still gets hot whenever the Kobo is connected to power - whether the power LED has been turned on or not, whether the battery is connected or not. I agree that this probably means the PMU is faulty, which is a pain; replacement batteries are easy enough, but fixing the PMU would probably require a new motherboard. I don't know what would happen to a healthy Glo HD with the battery disconnected, of course. I have seen a couple of reports which suggest that the same thing can happen with a fully drained battery, and in that case it'll fix itself if the battery can pick up a charge again, but that's just anecdotal. In my case there's some slight distortion visible on the PMU (not actual melting or discoloring, but with light at the right angle you can see the difference in what looks like a heat spot; there's what looks like a small dent in the back cover at the same spot), so I'm betting that the PMU chip is toast. Diagnosis notes: while the Kobo draws power (and gets hot) whether it's turned on or not, it will only show up as a connected USB device when turned on on Windows, you'll only get the "SE Blank MEGREZ" notification the first time you connect it (when Windows is setting it up as a new device) it will still be there on subsequent connections, but it doesn't show up in Device Manager as anything distinctive: just a generic USB HID device you can identify it with something like USBDeView (where "SE Blank MEGREZ" will show up in the Device Name column), or if necessary you can look for the device with vendor ID 0x15a2 and product ID 0x0063 it may or may not be easier to identify on other OSes; I haven't checked them, because I'm lazy Come to think of it, I didn't actually confirm whether it still behaves the same way with the memory card removed; I'll check when I get the chance. Based on the other reports (covering a bunch of different devices, not just Kobos), though, I'm pretty sure this mode is built in to the FreeScale SoC and so it'll only happen when no other OS is running, whether that's because of a faulty SD card, a blank one, or the lack of one entirely.