RooEUC Posted January 29, 2018 Author Share Posted January 29, 2018 2 hours ago, Knifa said: Alternate Imgur link for the images. I misjudged the cerb at a deep puddle, bonked right into it and fell off, with the unit falling sideways right into the water. Worked fine for maybe 5-10 minutes until it started juddering and making weird beeping sounds. I walked it home from there and let it dry for a couple of hours. Turned it on and it seemed fine. Turned it off and there was a big crack from where the power switch is, wouldn't turn back on again. The LED on the batteries turned red which I think means short-circuit protection mode. Took it all apart and discovered one phase of MOSFETs were shorted source to drain, despite looking visually fine. Removed them and the board started to boot again. The MOSFETs have the model number STP51810, which are rated for 100V 110A. Got some similarly rated ones (STP110N10F7) and replaced them on the board. Works good as new. Only thing that's fully dead is the blue light on the power switch, and also it seems to make a new ticking sound. I bet your heart sunk a little when that happened. Luckily you're electrically capable and were able to repair it yourself. I can do a fair amount of electrical repairs but I don't know if I'd have been able to diagnose and repair dead mosfets as easily as you did. I would probably have skipped to the step of looking for a replacement mainboard. Link to comment Share on other sites More sharing options...
Knifa Posted January 29, 2018 Share Posted January 29, 2018 19 minutes ago, RooMiniPro said: I bet your heart sunk a little when that happened. Luckily you're electrically capable and were able to repair it yourself. I can do a fair amount of electrical repairs but I don't know if I'd have been able to diagnose and repair dead mosfets as easily as you did. I would probably have skipped to the step of looking for a replacement mainboard. It really did! Sourcing parts for this series of EUC is really awkward so I was ready just to go ahead and get something brand new. To be honest, I was just poking around with my multimeter on continuity mode trying to find shorts where they shouldn't be. I have no idea what else is going on in that board. Link to comment Share on other sites More sharing options...
RooEUC Posted January 29, 2018 Author Share Posted January 29, 2018 1 hour ago, Knifa said: It really did! Sourcing parts for this series of EUC is really awkward so I was ready just to go ahead and get something brand new. To be honest, I was just poking around with my multimeter on continuity mode trying to find shorts where they shouldn't be. I have no idea what else is going on in that board. Haha yeah that's how I fixed the mainboard in my gas furnace heating system, just by poking around with the multimeter. I have submitted my return request and have to ship it within the next 3 days otherwise I'm stuck with it. The thing is, I'm worried I will regret this decision for the rest of the year, especially when Spring comes and I can actually ride it. I can't even test ride it again because of the snow. But will I even enjoy it when it can only do a maximum cruising speed of 19kph fresh off the charger? I know if it goes back I won't be buying another EUC this year (because any other option will be $1000+ CAD where I am and I'm not up for spending that much), hence the difficult decision. Link to comment Share on other sites More sharing options...
Knifa Posted January 29, 2018 Share Posted January 29, 2018 7 minutes ago, RooMiniPro said: Haha yeah that's how I fixed the mainboard in my gas furnace heating system, just by poking around with the multimeter. I have submitted my return request and have to ship it within the next 3 days otherwise I'm stuck with it. The thing is, I'm worried I will regret this decision for the rest of the year, especially when Spring comes and I can actually ride it. I can't even test ride it again because of the snow. But will I even enjoy it when it can only do a maximum cruising speed of 19kph fresh off the charger? I know if it goes back I won't be buying another EUC this year (because any other option will be $1000+ CAD where I am and I'm not up for spending that much), hence the difficult decision. It's such a shame the S1 is limited to 19km/h only because I think the unit as a whole is really great. The S2 gets 25km/h and I find this to be a decent cruising speed (for me at least, as my first wheel). Perhaps there's a way you can swap the board for an S2 board, or somehow flash S2 firmware? Link to comment Share on other sites More sharing options...
novazeus Posted February 1, 2018 Share Posted February 1, 2018 @RooMiniPro i was thinking about u today because i noticed some hissing coming out of my s2 today when i was screwing around with it on my tailgate. it’s not continuos hissing, just momentary. maybe it’s normal. seemed to work fine on our rides today. the batteries were at about 80% and that’s the lowest i’ve let them get so maybe that has something to do with it. idk. Link to comment Share on other sites More sharing options...
RooEUC Posted February 9, 2018 Author Share Posted February 9, 2018 @Knifa When you enquired with Ian about a new mainboard for your S2, did he mention a price? I know you fixed yours yourself but I'm wondering how much a whole board would be. Link to comment Share on other sites More sharing options...
Knifa Posted February 9, 2018 Share Posted February 9, 2018 6 hours ago, RooMiniPro said: @Knifa When you enquired with Ian about a new mainboard for your S2, did he mention a price? I know you fixed yours yourself but I'm wondering how much a whole board would be. No, sorry! He had only just started looking into getting the part when I told him I managed to fix it. There's exactly two dodgy looking entries on Aliexpress for the boards (dodgy in the sense that the pictures look like the 16" Ninebot boards), one being $150 and the other being $300. So I guess in that kinda range, maybe? Link to comment Share on other sites More sharing options...
RooEUC Posted February 9, 2018 Author Share Posted February 9, 2018 2 hours ago, Knifa said: No, sorry! He had only just started looking into getting the part when I told him I managed to fix it. There's exactly two dodgy looking entries on Aliexpress for the boards (dodgy in the sense that the pictures look like the 16" Ninebot boards), one being $150 and the other being $300. So I guess in that kinda range, maybe? Ah yes that’s the sort of price range I was expecting. Parts are few and far between for this wheel. I was thinking about putting an S2 board into my S1. I wish there was a way to flash the firmware. Link to comment Share on other sites More sharing options...
Knifa Posted February 10, 2018 Share Posted February 10, 2018 On 09/02/2018 at 11:59 AM, RooMiniPro said: Ah yes that’s the sort of price range I was expecting. Parts are few and far between for this wheel. I was thinking about putting an S2 board into my S1. I wish there was a way to flash the firmware. If we can figure out how to pull the firmware from the app, we might be able to pull the S2 firmware files and flash them straight up. I really doubt there's any firmware signing or security stuff going on. Decompiling Android apps is straightforward but I think what you get out of it is a horrible mess, so not sure how well it would work. OR doing it fully in hardware: There's nothing like a JTAG on the board but there's a bunch of unpopulated 2.54mm pin headers. On the underside of the board there are two pins marked RX/TX, so possibly a UART? They have to flash the chip during manufacturing at some point... The microcontroller onboard is a STM32F3. If the pins underneath are indeed for the microcontroller's UART, and they're using the stock STM32 bootloader, it should be easy to both read the firmware off and write to it. I've got a STM32F3 dev board here with the ST-LINK debugger so I might be able to have a play around. I'd need to take my whole wheel apart again, though. Link to comment Share on other sites More sharing options...
Knifa Posted February 10, 2018 Share Posted February 10, 2018 I started having a poke at the Android APK but it's packed with Bangcle so decompiling it is a pain. Link to comment Share on other sites More sharing options...
RooEUC Posted February 10, 2018 Author Share Posted February 10, 2018 I can do most hardware tasks and I used to work in I.T. but to be honest, a lot of what you said was like a foreign language to me. If you can figure out a way to do it that’s repeatable I think you could make a nice bit of cash as I’m sure I’m not the only S1 owner who would gladly pay to upgrade to S2 firmware. I have started to really love my S1 now, but the slowness is so annoying. It feels so wrong on an EUC. And knowing that it’s artificially limited by 4-6kph just for Americans is even worse because I know this wheel has more potential. I was heavily involved in the MiniPro speed hacking project we had going on this forum, so I don’t mind tinkering with my gear. I just don’t know much about ripping firmware out of phones and getting it onto a chip. Link to comment Share on other sites More sharing options...
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