RAI

Mike, This is a stand up, electric scooter, so there's not much to break on it. Except of course, the throttle, which is (after inspection) quite fragile/vulnerable in a crash. I managed to wrestle the new throttle apart. It does, indeed, have TWO magnets in it. They're mounted about 90 degrees apart, so one or the other of the magnets is near the hall effect sensor at the rotation limits. I'm convinced that they sent me a bad throttle. Its sensor just is not responding to the position of the magnets. It's all wired fine, with no breaks in the wires nor thru the connectors. d8veh, I looked at controller alternatives. Seems that e-bike controllers are a fair bit different than scooter controllers. I'd been hesitant to go this route because I couldn't determine what the motor specs are. This scooter is about 8 years old and obsolete. There's hardly Any information on it Anywhere. I Could replace the controller (I'd guess a 250watt model would work) but I need a new throttle, so it'd cost me $30 ~ $40. We have a thing here called Craig's List, it's like a bulletiin board service where you place classified ads. I checked and there are several scooters for sale by owners. Razor brand, going for $50 to $120. I'm more inclined to buy one of these and start off fresh. These are only a few years old and parts will be more standardized and common. I'll end up buying new batteries again, but that's pretty painless. So, that's probably what I'm going to to. I'm sure that I could continue to work on this old scooter and get it working (either the new controller route, or try another throttle) but frankly, I'm tired of looking at this old thing. Thanks everyone, for your comments and suggestions. Cheers, Roger

Had other stuff to attend to, but finally got back to this. Zombie, I originally tried using a new UGN3503 replacement hall effect sensors in the old throttle. I followed the spec sheet, but it didn't do anything. Grasping at straws, I started swapping wires around, but still no luck. Turned out that the magnet wasn't where it should've been. With the new (suspected backwards polarity) throttle, still no luck - no response. d8veh, for the yellow and blue wires, using my volt meter, there's 5v from red to yellow and 4.97 from blue to yellow. This is measuring on the controller end of the cable with the throttle disconnected. I dug out an old 5kohm pot and put it across the controller end of the cable. With the pot across red and yellow, with the wiper on blue, the motor runs fine, and the voltage sense is still backwards. High voltage is stopped, low voltage runs fast. The odd thing is that there's only a 0.5 volt range from stop to full speed; and it's offset, too. Specifically, 3.0 volts is full speed, and 3.5 volts is full stop. Very narrow range. This is with the wheel off the ground though -- maybe it has a wider voltage swing under load. Still, this doesn't explain why the output voltage on the new throttle that I bought, doesn't change. It confirms that the controller is probably still okay (caveat on the voltage range). And it confirms that I didn't have any wiring misunderstanding. Red is 5v, Yellow is Gnd, and Blue is control voltage. I searched for several hours, trying to find a local source for that $3.00 resistive throttle from EV Assemble. I thought that place was in England... It's actually in China. Shipping that throttle to England is still 20GBP (plus 2GBP for the part itself). Other resistive twist grip throttles are available here, but for some reason, they're like $50 or more (all seem to be "Magura" replacements). Compared to those, the one you suggested is still a bargain, but I can't bring myself to spend $31 for shipping a $3 part. I have one last thing to try before I throw in the towel, take the SLAs out and drag this old scooter out to pasture (so to speak). I'm going to take apart the new Hall Sensor throttle and make sure that I see nothing wrong with the magnet, sensor, etc. IOW, see if I can figure out why it's not responding. Perhaps the magnet simply fell out and isn't where it should be. <sigh> Roger

The throttle came with a sheet of paper detailing the wire colors and it has a red stamp: "CHECK PASSED" or something like that. So, I would hope that the wire colours aren't swapped. Of course they could just put pre-stamped papers with every unit without actually checking them... I was also thinking that the signal and gnd might be swapped; but it doesn't quite fit with what I'm seeing. I might go thru all the possibilities on paper to see if any combination of wires agrees with my observations. The controller wires are red, yellow and blue. I think the old throttle wires matched. The new throttle wires are red, black and green. Red seems to be consistently 5v. You'd think that they'd be able to consistently make gnd a black wire...

My $15 hall throttle arrived yesterday and I gave it a go... so I'm back with news Mike K. - nah, no one calls me lucky... in fact, my lack of luck in this matter continues flecc - might be two magnets... didn't see any curved magnet. I'm thinking that the sensor basically works on seperation distance from a single magnet. d8veh - Thanks for the link on the pot throttle. Unfortunately, although it's only $3, shipping to the states is $29! Perhaps I can find it closer to home. As you may have guessed by now, the new throttle isn't working any better. I had to cut and splice the old connector onto the end of its cable. Anyway, it's acting just as dead as my other attempts. I'm really getting befuddled - and I'm an electrical engineer! With the new throttle connected, the 'output' voltage is stuck at about 4.2volts. The power is dead on at 5.0 volts. Twisting the throttle handle has no effect. I was expecting it to work backwards, but it does nothing. I was starting to think that my controller died, but with the throttle cable unplugged, shorting the sense wire input to gnd still causes the motor to run full speed. I put my meter in current mode and the the current is 0.5mA, which makes sense if there's an internal 10kohm pull up resistor to 5v. I believe that the hall sensor has an open collector output (i.e. a transistor that pulls the sense voltage down towards 0v, & lets it get pulled back up by the 10kohm resistor). My point is that the controller input seems to be fine and it agrees with the sensor having an open collector output. So WHY doesn't the output from the sensor actually pull the voltage down based upon the throttle handle position!!!! ARGH! I may try digging out an old pot from my old parts boxes. Unfortunately, I think most of the ones that I had were either 10-turn or log taper. Maybe I'll get "lucky". I have a suspicion that maybe I'm misinterpreting the wires(?) so fiddling with a pot might make that clearer. It's got to be some stupid simple error (I hope). If that's the case, and I can get this hall throttle to respond, then I may come back to flipping the magnets around. If not, then maybe I can find that $3 throttle nearby. Thanks all - wish me luck! Roger

I've managed to figure out how to open up my broken throttle. I used four bamboo (shishkebob) skewers to release four plastic spring tabs inside it. The magnet is very small (about 3x3x8mm) and it's mounted 'vertically' on a piece of plastic that looks like it was also the rotation stop. When my son ran into the hedge, he must have twisted the throttle forcefully forward, breaking off the plastic tab (and magnet). That doesn't fully explain why my sensor replacement efforts were so unsuccessful, but it's part of the puzzle. I've been emailing around asking the same questions. I found a place in Idaho that convincingly has the correct throttle that I need, but they want $30 plus shipping. 2 or 3 other places agree that my throttle is backwards, but don't sell what I need While 1 place basically says don't worry, buy ours and it'll work I found one place that only wants $15 w/shipping for the same throttle that the others are asking for ~$22 w/shipping. SO, I'm going to give that one a go, and try to flip its magnet around. I hate to say it, but if that doesn't work, I may just give up. With Christmas approaching, I have many other things I should be doing. I got the scooter for free from a neighbor. My only regret will be that I spent $75 for new batteries for it. (But I should be able to re-purpose them to one of the computer UPS's in my house.) Of course I'd like to get it working again, but my son tends to be hard on things, so 1) he may just go out and crash it again, and 2) it might be a lesson to him to lose the use of his scooter due to his crashing it. I've also had to buy a new charger for it (he lost the old one), & had to rewire the connector for it, repaired its power switch (which he broke in another crash), spent for the hall sensors that didn't work, and will have to get new tires soon as they're getting 'bald'. I'm getting weary of keeping this "free" scooter running. My son and I thank you for your help, maybe d8veh can add something, too. Roger

I have an old scooter that ran well with a hall effect sensor throttle, at least until my son crashed it into a hedge. The throttle wires broke, so I took it apart to repair it. Whle doing so, I broke the wires off of the sensor. So, I ordered a couple replacement sensors (UGN3503U shipped from Hong Kong). They're smaller than the original, but same part number. I carefully soldered one in the manner that it apparently should've gone in; but I could not get it to work. Waving it around a magnet and moving it around in the throttle, I could barely get the output voltage to budge by 0.1 volt or so. I swapped pins 1 & 3 (+5 and output) but that didn't do much at all.Thinking that I'd perhaps burned it out by initally have 1&3 swapped, I tried my second part, with 1&3 swapped from the first go around, then when that did nothing, I swapped 1&3 yet again. So now, I probably have 1 broken sensor and 2 burned out sensors… Scooter is still not working… Laddie not happy... SO - I decided to look for a whole new throttle. The existing throttle looks identical to several Chinese hall effect sensor throttles that are for sale on many websites (about $20USD). HOWEVER, while I was trying to get my repairs to work, I noticed that shorting the output to GND makes the motor run full throttle, while shorting the output to +5v (or leaving it disconnected) leaves the motor idle (stopped). This is where I hope that some experienced chaps here can assist… (I'm assuming that pedelec throttles are very much like electric scooter throttles.) Isn't this backwards? From the info that I can gleen from the web, the voltage for full throttle should normally be up at +4volts, while +1volt should be stopped. My controller is expecting the reverse of that. Low (i.e 0)volts is full throttle, while high (+5) volts is stopped. Which way is, in fact, "normal"? And is my throttle "normal"? I believe that it was flecc that said, in another post about a broken throttle, that flipping a magnet (or two) in the throttle can change the "polarity" of the throttle. It seems that if I purchase a new throttle, I may have to do this flipping. If so, can someone tell me how to open up this type of throttle to flip the magnet(s)? I can't see how to open it up. My throttle looks exactly like this one: Scooter Throttle, Electric Scooter Throttle | Monster Scooter Parts I'm also curious if anyone (flecc?) has any insight into why my hall effect sensor replacement efforts were such a dismal failure. I was very careful, used a very small soldering iron and surgical forceps on the leads to keep the sensor from over-heating. Thanks in advance & Cheers, Roger