Basic controller repair question

Thread Starter

Saturnspattern

Joined Mar 22, 2021
2
Hi all. Hopefully this is a simple question!

I work for a mobility company and we have many mobility scooters come in with programming issues.

The controllers are S Drive unitscr-i2.jpgScreenshot_20210322-211602.pngScreenshot_20210322-211542.png



The main common issue we have is that when the scooter is coming to a stop from travelling forward it creeps backwards momentarily before fully stopping, and vice versa when reversing it slows then goes forward before stopping. In that case we swap the controller for another one and the issue is usually solved.

So my question is, is this caused by a component failing on the circuit board and would it be possible to replace? As a properly functioning scooter slows gently then stops with the electronic brake engaging and clicking when it stops. I believe something is telling the motor to operate when it shouldn't be, a chip or component possibly? This is where my knowledge runs out. I have soldering experience, although basic, but I'm looking to see if it's more economical to repair rather than replace every unit that comes in faulty. Many thanks for any help.
 

drc_567

Joined Dec 29, 2008
1,134
If the problem is related to the power drain that is required to brake the vehicle, then a possible component to check would be the set of 5 electrolytic capacitors, shown near the lower part of the photo. The reasoning is that electrolytic capacitors have been known to age, and exhibit deterioration. As a test, try desoldering the capacitors and replacing them with new ones. Be sure to install the new parts with the same polarity orientation, as marked on the side of each capacitor, as the original.
... The replacement capacitors should have the same voltage rating, or better, as the originals, and also the same capacitance value.
... No guarantee, but maybe worth a try.
 

Delta Prime

Joined Nov 15, 2019
1,054
Hello there :)
Welcome to AAC!
Model number serial number of the controller please.have you thought of contacting the manufacturer of this common persistent problem. A schematic would be wonderful.
 

wayneh

Joined Sep 9, 2010
17,153
If the problem is related to the power drain that is required to brake the vehicle, then a possible component to check would be the set of 5 electrolytic capacitors, shown near the lower part of the photo. The reasoning is that electrolytic capacitors have been known to age, and exhibit deterioration. As a test, try desoldering the capacitors and replacing them with new ones. Be sure to install the new parts with the same polarity orientation, as marked on the side of each capacitor, as the original.
... The replacement capacitors should have the same voltage rating, or better, as the originals, and also the same capacitance value.
... No guarantee, but maybe worth a try.
I agree this is an easy and cheap thing to try, with a fairly high chance of helping. Capacitors age. Many, many electronics head to the dump because of a bad cap or two.

If it doesn't fix it outright, at least the board will have fresh caps going forward.
 

Thread Starter

Saturnspattern

Joined Mar 22, 2021
2
Thanks for the replies! I can certainly swap out the capacitors on a dodgy unit and try it. Unfortunately I can't find any schematics online as there's very limited information on them, hence the question.
 
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