iGo -- No Go ! ..

Well, it seems they keep failing and coming my way.. izip .. schwinn.. Raleigh.. Giant.. now iGo's !

This poor iGo came to me a couple months ago with battery issues, moisture got in there and caused the BMS to shut down, after checking all cell voltages and sun drying for a while it came back to life and all was good since.

Last week customer had a crash and the throttle wires got ripped out of the throttle body at the hall sensor itself.. but the bike kept running with pedal sensor input for another 5 days. then it quit ... and arrived here .

I replaced the throttle with a tested / known good unit, the display will power up, the head light will function on/off, the high medium low function changes with button presses but the motor will not budge.. Throttle and Pedal Sensor both not responding at all.

Pulled the wire harness out of the frame ( no fun... not a good wire harness .. ) and discovered color combo's mixed along the way but traced the throttle wires all the way to the controller and confirmed continuity, cut the throttle connector and soldered it to remove that possibility.

One of the brake levers was bent pretty bad so that was a possible issue.. tested the sensor and they are ok, i cut the wires from both just to make sure ( tested open circuit operating, closed circuit when brake lever pulled )

following the Red and Black wires from the throttle and pedal sensor to the controller board i get 1.2v on the throttle pins and 0.4v at the pedal sensor with the controller powered up and display lit.. .. i believe that should be 5v .. right ?

Backside of controller

View attachment 1

So my question is this : Is it possible for the throttle wires shorting out to kill the controller somehow ? yay or nay ?

Yes. short the 5V to ground, and you might have killed the 5V side of the board. Something has to drop the 13v to 5V. It could be a 7805, a MC34063, or even a ziener diode. Any of those could be blown by being shorted.

left forward section of controller in bottom pic, probably is a type of smps to lower the battery voltage to 5v, maybe 12v and 5v, so you may have no direct regulator, just that switching supply.

I sure wish i understood that language.. ..

you are asking if having a short between the +5V to the throttle and ground would damage other parts on the controller?

if you disconnect the throttle signal wire from the pcb then if it is shorted through the signal line it should allow the 5V to rise. so if it climbs up you would know if the voltage regulator section (that he says is a switch mode power supply type) is ok. so if the 5V comes back then the controller should be ok imo.

if it doesn't climb then cut the red wire and see if the solder point on the pcb climbs to 5V.

or disconnect if there is a plug.

Ypedal said:

I sure wish i understood that language.. ..

Click to expand...

Which part?

If any of the 5v wires were shorted to ground for any length of time, the 5v regulator woyld blow. I can see what looks like the 12v regulator, but not the 5v one. Can you photograph the rear part of the circuit board from the top and stand up that big capacitor? You should also measure the voltage on any of the 5v wires with the motor halls, brakes, throttle and PAS disconnected in case there's a falt in any of them that pulls the 5v down.

The control panel works independently from the controller. It has its own supply from the battery. The only thing it confirms is that the battery is charged.

I cut the throttle +5v and Signal a few inches away from the controller ( so i can re-solder them back on if need be .. ) .. and also cut the 3 PAS wires .

Tested voltage between all 5v pads and grounds and only getting 0.8xx volts ( was getting 0.4 v prior ) ...

I just now grasped Dnmun's request of also cutting off the 5v wire from the hall sensors.. going out now to try it.

The 5v hall sensor wire is not soldered to the board inline with the other hall sensor wires, it feeds to the same 5v as the right side red circle ... i cut the 5v ( red ) hall sensor wire 1" from the board.. powered it up and tested again..

I get 1v between most pads and -2.7v between TOR and +5V pads .. .. but nowhere do i get 5v

so the switch mode power supply that AW was talking about may be dead now. it is over in the lower left corner where the orange wire comes back from the switch. that transistor may be cooked so see if you can read the label on it and we can google it and get the pinout for the legs and test it.

i think U9 is the 5V regulator so that would be where your 5V comes from so look for 12V on the leg that comes to it from where the SMPS is located. the middle leg of that U9 is the ground i am fairly sure.

also i think that led D16 would be lit if there is 12V from the SMPS. see if the traces go to the capacitor on the output of that inductor there.

More pics help!

U9, the black square in the center of the board, that should be a surface mount version of the LM7805. (could also be an LM3XX, but I doubt it)
I believe the pin on left hand side, closest to the front in the picture is the output, +5volts. the rear left pin should be the source, so +12v. The right hand side will be used as the ground. But I'm pulling all of that from memory.

I think what Amberwolf was pointing out is what drops the 36v down to 12v. it's very unlikely, but possible that a short killed the 12v side, causing the 5v side to not get enough power. Or there could have been a cascade failure. But either situation is extremely unlikely.

If it is just the 7805, it's an easy fix.

something else could drag the 5V regulator down too. they are usually designed so that a short on the output is not fatal i would expect.

if the led is lit and there is 12V to the 5V regulator input and the 5V rail is still only 0V then maybe unsolder the 5V leg and lift it from the trace to verify that the 5V regulator would still put out the 5V by itself.

then look for the short somewhere on the 5V rail if the 7805 will push 5V while unconnected. it would be ok then.

should be obvious how this is all so new to me, learning how to diagnose this stuff like AW does all the time. but it is on my bucket list.

the capacitor on the 5V rail could be shorted. hate to think the microprocessor is shorted, even more unlikely imo.