alcatraz Posted July 27, 2022 Share Posted July 27, 2022 Hey everyone. I got a malfunctioning MSX (won't power on, nothing obviously burnt) and I'm not in a hurry to fix it. What basic measurements can I do with a multimeter to rule out components? Resistance between motor wires? Resistance between output to ground? Voltage on hall sensor wires? Resistance between mosfet pins? Resistance between mosfet pin and heatsink? I don't really have reason to suspect the motor but I'm happy to rule it out. It spins freely when connected to the board. Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 27, 2022 Share Posted July 27, 2022 12 hours ago, alcatraz said: What basic measurements can I do with a multimeter to rule out components? Check how far the battery voltage comes - if it arrives at the legs of the big capacitors. If not, check if it arrives if only one battery is connected. Try both batteries alone at both connectors. (If there are both connectors). Check the path from the batteries till the big capacitors and eventually to the dc/dc converters. Check all supply voltages - ?12V? for led's (pattern, front and back). 5V at the hall sensor connector and ?3.3V? at the ic's (at their blocking capacitors). If supply voltages are "missing" check the dc/dc converters. 1 Quote Link to comment Share on other sites More sharing options...
Tawpie Posted July 27, 2022 Share Posted July 27, 2022 Assuming it just up and decided to not power on for no obvious reason, have you checked the power switch to see if it's working? I'd disconnect it from the motherboard, then measure the switch side of the connector for resistance when pressing and releasing the switch. It's probably open circuit when released and closed (not infinite resistance) when pressed. If I knew for certain the power button was 'normally open' I'd try using a jumper wire to short the connector contacts together (hotwire it!) and see if that works. But I don't know how the power button is supposed to function so do NOT do any shorting together until you're certain! 1 Quote Link to comment Share on other sites More sharing options...
Begodecrashtestdummy Posted July 28, 2022 Share Posted July 28, 2022 Definitely pop out and check the power / charge port soldering .when I did a shell swap on my rs19 high speed the soldering on it looked like a 5 year old did it .so I resoldered it.plus the two tiny wires that go to the power button where barely connected like they were ready to break ..so I fixed them aswell .as far as the dc converters go .when my dc converter went it still powered on and balanced and rode and charged but I lost my lights,display screen and the fan would just stay running at a slow speed all the time instead of just kicking on when it reached high temp warning 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 28, 2022 Author Share Posted July 28, 2022 (edited) Great ideas everyone! Thank you so much. The wheel cut out on me at low speed on a flat surface (I just crossed a half recessed train track). I suppose it could be because of a short. Better check all the wires. If positive is shorted to ground somewhere it could explain why the caps are discharging. The charge port could be the culprit. The board looks fine. Does shorting of a charge port mid ride cause a cutoff? It does on begode, doesn't it? (i've got older wheels) Edited July 28, 2022 by alcatraz Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 28, 2022 Author Share Posted July 28, 2022 33 minutes ago, Dosingpsychedelics said: Definitely pop out and check the power / charge port soldering .when I did a shell swap on my rs19 high speed the soldering on it looked like a 5 year old did it .so I resoldered it.plus the two tiny wires that go to the power button where barely connected like they were ready to break ..so I fixed them aswell .as far as the dc converters go .when my dc converter went it still powered on and balanced and rode and charged but I lost my lights,display screen and the fan would just stay running at a slow speed all the time instead of just kicking on when it reached high temp warning Great! Is the dc converter next to the control board? When I got my wheel it had been retrofitted with speakers. I took out a board on the left side (non control board side) as well as the speakers. I hope that wasn't a part of the wheel. The wheel did 4000km afterwards so I'm assuming no, but reading your post left me wondering. Quote Link to comment Share on other sites More sharing options...
Begodecrashtestdummy Posted July 28, 2022 Share Posted July 28, 2022 (edited) The dc converters are sometimes with the motherboard and sometimes separate.on my wheel rs19 hs they have now made them seperate and not all connected to one board .it’s way cheaper to replace now .im not sure how they are on the msx but here is a picture of the dc converter it’s those two yellow things Edited July 28, 2022 by Dosingpsychedelics 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 28, 2022 Author Share Posted July 28, 2022 I've got the damn dc converter on the control board. I wonder how to diagnose it. @Chriull The pack voltage makes it to all three capacitors. With the pack disconnected my multimeter reads 449ohms between the positive and negative side of the input/caps. That sounds low to me. Maybe it explains why the caps are discharging so fast. I disconnected everything except power switch (confirmed working with multimeter at the board connector), and I get no reaction when trying to power on. @Dosingpsychedelics wrote that the dc board could be broken and that sounds possible. I'm curious as to how to recognize the input and output of it. (integrated kind) Does the control board need a dc-converter to be able to power on? Would a broken dc-converter cause a cutoff? The charge port and power switch cables look fine. They're heatshrinked. It seeems that the charge port only connects to the packs and not to the control board. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 28, 2022 Author Share Posted July 28, 2022 15 hours ago, Chriull said: Check all supply voltages - ?12V? for led's (pattern, front and back). 5V at the hall sensor connector and ?3.3V? at the ic's (at their blocking capacitors). If supply voltages are "missing" check the dc/dc converters. Do you know if supply voltages are available with the wheel off? I can't turn it on. Hmm... Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 28, 2022 Share Posted July 28, 2022 46 minutes ago, alcatraz said: I've got the damn dc converter on the control board. I wonder how to diagnose it. @Chriull The pack voltage makes it to all three capacitors. Great. 46 minutes ago, alcatraz said: With the pack disconnected my multimeter reads 449ohms between the positive and negative side of the input/caps. That sounds low to me. Maybe it explains why the caps are discharging so fast. No, that's most likely some bogusly shown value by some dynamic processes. There is no conclusion to be drawn by this. 46 minutes ago, alcatraz said: @Dosingpsychedelics wrote that the dc board could be broken and that sounds possible. I'm curious as to how to recognize the input and output of it. (integrated kind) Depends on the used ic. In the datasheet one finds recomended schematics. As written supply voltages should be near the led drivers, at the hall sensor connectors and blocking capacitors of tge ic's (μC, gyroscoe, ...) 46 minutes ago, alcatraz said: Does the control board need a dc-converter to be able to power on? Would a broken dc-converter cause a cutoff? Yes. The dc/dc converter drives the μC which runs the firmware and controlls the bike. 46 minutes ago, alcatraz said: It seeems that the charge port only connects to the packs and not to the control board. That's only the newer motherboards that control charging. From Leaperkim, KS and Inmotion. Don't know if any behode has charging wires going by the motherboard. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 28, 2022 Share Posted July 28, 2022 55 minutes ago, alcatraz said: Do you know if supply voltages are available with the wheel off? I can't turn it on. Hmm... Yes. Afaik the power button is read by/wakes up the μC which starts balancing. So it needs power supply all the time. Other power supplied could be turned off inbetween and be enabled by the μC. 1 Quote Link to comment Share on other sites More sharing options...
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