Non Bio - Electronic repair needed please

[K.H]

Im trying to get this repaired, its from a cheapo Chinese electric bike (my fathers), replacement parts are non existent.
The part at the front with the curved wire is definitely broken,





And i guess the rest needs checking.

This part hopefully just needs soldering back together



Within reason price is not a issue, need to get him back on the road!

[julianf]

Alan is the one for electric bikes.

The broken bit in the lower shot - is that a ir rev counter part?  If so, that's an off the shelf bit.

[kamaangir]

Looks like a couple of blown electrolityc caps, there is a diode and a wire wound resistor that look shot too. I will bring a multimeter and some one is bringing me a scope, between us we should be able to sort them all out.

[Twenty4Seven]

The bit with the curved wire looks like an IN4148 - pennies to buy.

The bit in the lower pic is, as Julian says, most likely an IR pulse sensor but could (less likely) be a Hall-effect sensor. Any numbers on that part?

[K.H]

You will have to excuse my ignorence on these electrical terms, i havent a clue
The bottom pic - the pedal shaft has two sets of fins which rotate between the U shaped things
I guess this controls the motor assist?
As an aside it also has a throttle type control, the pedal shaft part is just to comply with UK regs AFAIK, if this was bypassed it wouldnt be a problem to me

[Tony]

That diode could also potentially be a zener diode for a reference voltage. Are there any markings on it?

[photoman290]

the problem with blown parts is what else they took out when they blew. not helpful i know but just changing the blown parts may not work.  worth a try though. the broken bit in the bottom pic is most likely a IR counter.  there should be a number on it somewhere.cheap and easy it fix. i have a friend who could have a look at it if you get stuck. he is well into his electric bikes and is also an electronics enginner.

[julianf]

Diode markings are always very hard to read.  Even when theyre loose, on the desk, in good light.

These two are the same, but have the writing in different orientations -





both 1N4148.  Im posting the images as an example of what to look for / how hard it is to see.

I assume there's no hope of soldering the wire back onto the body?  It does not look like there is a stub, but it may be a consideration?




On looking further, im almost certain that the other parts are a pair of photoswitches.  Here is a photo of some fresh ones -



They are not big money - couple of quid each or so.

[julianf]

the problem with blown parts is what else they took out when they blew.

That's always my thoughts with the 'fix by looking at it' technique, but it looks, in this case, as the damage has been physical, rather than electronic?  Ie somone has whacked it, and things have snapped, rather than a more 'technical' fault? : )


(ive always had very poor results with 'fix by looking' but then i know others have more luck than me)

[K.H]

Yes, definately need the whole thing checking as suggested, the bottom part was bust by me dismantling

[knighty]

what voltage is the battery, and how many watts is the motor ?

new controllers are pretty cheap (£20 ish)

it's probably easier just to replace it for new

it's easiest just to put a normal controller with a throttle on it... unless your dad likes the pedal assist feature (where you pedal and it helps) for the exercise ?

[K.H]

This is built in to the pedal shaft unlike most others where you can buy a module

[knighty]

can you put up a photo ?

vast majority of e bike stuff is pretty much the same

[therecklessengineer]

Sounds like a PM sychronous machine. Funnily enough...just writing a masters thesis on them.

Stick up some photos - most motor types can be driven with an off the shelf controller of some sort.

[K.H]

These both say WYC576



This is the whole "electric control unit" which fits in the bottom bracket with the pedal shaft going through it, Pedelec style



Very similar bike




Ive had a closer look at the board, i cant read anything on the "diode" but there is an identical one one the other side? which says 15T i think
The Blue coloured thing to the left of it has a bust leg this says "D81 CD8" those are the only damage i can see