Greetings,
I have a 9 year old Pride Pursuit XL which has recently been stopping DEAD. At first I thought it was the loose caps on the motor brushes. After tightening the two loose ones, it ran perfectly for weeks. Today, it died again. I wiggled the smaller wires going into the controller (not the 4 major ones) and it turned back on. Upon getting home it died again and no amount of giggling would turn it back on. Should I remove the controller and open it up?
A few years ago it stopped working and two costly visits to two different repair shops here in B.C. ended with them not being able to fix it. (They gave up.) Looking around, I found a broken fuse on one of the battery cables....replaced it and it was perfect for years....until now.
Any suggestions? I have a multimeter but am not good with electronics.

 

Welcome to AAC.

First, my apologies in advance for this but I can suppress it...

...it died again and no amount of giggling would turn it back on.

Did you try LOLing? Sometimes it might even take a solid ROFLMAO to convince these things to work.

OK, now that I’ve got that out of my system... Ssorry, it might be that I have six kids making me far more disposed to the dad joke impulse than average).

First, the good news: it’s actually not working any more. This is much better than an intermittent fault which is the worst condition for troubleshooting something. This may seem cold comfort but it makes things easier.

Now, the “bad” news. A scooter is complicated. Electrical problems with vehicles—scooters, e-bikes, cars, &c—are notoriously hard to track down because of a combination of many wires, hidden pathways, and vibration & environmental exposure which can do hidden damage to components, housings, and wiring harnesses.

So this mean you are up against a potentially complicated problem but it is just a matter of systematic approach.

There are only a few troubleshooting techniques required to fix any mechanism. The first one that you need to empty is signal tracing. In this case, depending on the exact state of the scooter, the approach will vary a bit. When troubleshooting, the fist thing you have to do is assess the state of the device.

You can classify this in three ways:

1. Intermittent
2. Weak
3. Dead

As I mentioned, you are no longer dealing with the first, and that’s good. But which of the others do you have? A weak device “works” but doesn’t achieve the expected output. This can be in various forms. For example, in the case of your scooter, it could be the scooter runs but can’t go as fast as it should—this is one version.

Another might be that the backlight on the display works but nothing else, or it seems to be OK but it just won’t run. The idea is, with a weak device you can use that fact to eliminate certain possibilities or include them.

A dead device simple doesn’t operate. Nothing lights up, makes noise, or moves. The difference between “weak” and “dead” depends on the (sub)system of interest. For example the scooter might be weak if it lights up as usual but won’t run while that state of affairs would lead to a dead classification for the drive system in isolation (on our first pass).

This process helps home in on the areas that should be investigated.

The very first signal tracing we must do for a dead device is to trace the power. It is unfortunately very easy to overlook a simple solution if this isn’t done. (see: your discovery of a bad fuse) This is why “is it plugged in?, is it turned on?” are not insulting questions when troubleshooting, everyone is vulnerable to ignoring these things and spending a lot of wasted time on looking elsewhere. Always despise of these two questions first with a visual inspection and electrical testing as required.

If a casual inspection of the power source, the power inputs, and any wires, connectors, and switches that are involved is the first step. That is, other than using a meter to check for power at the source, which is the very first signal tracing to do. A visual inspection can reveal something that can be seen but it doesn’t help with invisible faults and so measurement is always necessary.

If you have or can get documentation on the internals of the device, preferably a service manual, this will often include test point (TP) voltages which can allow you to much more easily trace the power. Abnormal voltages are a clue to the problem area. Even without a manual, the same basic idea is employed.

Systematically trace the power unless and until it stops propagating. If you have power at one end of a cable, say, and not the other, the cable and its associated connectors will be the culprit and you can change focus to that. Sometimes we have spares on hand and swapping out the part is a way to test.

But let’s say you do that and it still doesn’t work or you pull the cable off and check it pin finding them all working. Well then you’ve isolated the problem to the connectors the cable plugs into, etc. The key is a stepwise and rigorous trading to the power form the source (battery) to the consumer(s).

The idea of jiggling (or wiggling) the wires is a good one, and is part of the visual inspection process in many cases. The trouble comes when you assume that because moving one thing makes things work the thing you moved is the actually problem. Things are attached together and moving something can move something else you aren’t paying attention to.

For this reason, at the start forget about the fact that you seem to have been able to “fix” is with your laughter—err, movement. Start with a clean slate and keep that detail in reserve for when I might gain some context because of electrical testing.

Obviously this is a complicated topic, but go at this systematically. Start by checking the battery, its leads, the connector on the terminals, fuses, &c. But back up your impressions with measurement. If the battery is 24V and you have 24V at the terminals, does the 24V make it all the way to the controller? If not where does it stop?

If it does, this is where you can take out the controller and do the same thing starting with the power input. Does the power appear on the connector pins? Does it appear along the traces connected to the pins? If it stops, what is between the input and that point, it is suspect.

This could turn out to be a simple, unexpected problem but it could also be the interaction of more than one system, so if oyu want to try to fix this you must relax, be systematic, and document everything you do. Taking photos, drawing wiring diagrams, schematics, and notes is very important with a complicated device. First so you don’t repeat things unnecessarily and second so oyu can refer to something other than memory when some discovery makes you question an earlier activity.

If you trace the power system and come up empty (that is, it all seems to be intact) then you need to move on to the power control system. This is the same process over again but will take a bit more knowledge to work out. The first step for this is to check all the components that run the input power into something useful to the board (e.g. PCB traces, protection devices like fuses or diodes, buck or boost converter parts, &c. Basically everything the input voltage is supposed to pass through.

But first, thoroughly check the power supply system, its wires, and connectors. Then if that all actually seems fine, come back for more advice. The documentation you have done will be very useful for those wanting to help. Sharp, well lit photos or the parts and connections that you collected will make helping you much, much easier. And, any other documentation you uncover during research (like, a service manual) will be as well.

Good luck! And don’t let the frustration of a tough troubleshooting job get you down, keep laughing at the scooter, it let’s it know whose boss.

 

First, the good news: it’s actually not working any more. This is much better than an intermittent fault which is the worst condition for troubleshooting something. This may seem cold comfort but it makes things easier.

“Would you mend my amplifier - it’s got an intermittent fault”
”Take it away and bring it back when you have broken it properly. Then I can fix it”
One important tip for fault-finding: don’t go looking for complicated faults until you have exhausted all the simple faults. Simple fault are a LOT more common.
This is especially true if you are called in to fault-find on a repair that someone else has already started trying to repair.
Never assume that your colleague (no matter how well you know him) has checked all the really obvious things.

 

“Would you mend my amplifier - it’s got an intermittent fault”
”Take it away and bring it back when you have broken it properly. Then I can fix it”
One important tip for fault-finding: don’t go looking for complicated faults until you have exhausted all the simple faults. Simple fault are a LOT more common.
This is especially true if you are called in to fault-find on a repair that someone else has already started trying to repair.
Never assume that your colleague (no matter how well you know him) has checked all the really obvious things.

Unfortunately it is much more profitable to assume that someone missed the device being unplugged or switched off—or "turned down"—than to assume they would have spotted it.

Sometimes, in an effort to remove blind spots, I pretend that I was just handed something someone else (in this case, the suspect versions of me). I pretend that I am trying to prove how much better I am at troubleshooting and make the assumption that previous me was sloppy and lacked rigor, if not just incompetent. That's when I discover the hard power switch I didn't know about, or the power cord not seated, &c.

I learned to do this because I was providing support for users on computer systems and applications. They would report what I knew to be an impossible combination of symptoms and circumstances, and so I would ask them to reproduce it for me. When they tried, to their amazement, it worked.

I would tell them the computer was afraid because I was there and knew the reported problem was impossible so it couldn't fool me but was happy to troll them in their ignorance. This happened enough times that I felt I needed to work out what was going on. Many of these users were really quite competent with the software and the problems were very mysterious. Something was happening, but what?

I finally came to a conclusion which seems to explain it. It was the same "problem blindness" I was familiar with in my own attempts to fix things. They'd just been trying over and over to do something that wasn't working but when they needed to prove that the impossible was, in fact, happening, they would be very careful to do each step of the process they knew was required.

Because of that, they didn't miss the step they'd left out over and over when I wasn't there. But then doing all the steps made it work, miraculously it seemed. This general idea is why I am a great fan of checklists for things not frequently done but also things done so often we become blind to the actual steps.

If you change something in the environment or add a new step it can derail the automatic process that used to work in a way entirely invisible to the user. A checklist to fall back on is a great tool. So much to say on this, but...

 

Thanks, so much, for the procedure process. It helped keep my efforts organized and I believe I have found the problem. I took the whole scooter apart, including the controller. All the main cables were tested for continuity. I found that by moving the wires that run into the controller....the smaller ones, NOT the battery or other heavy cables....that I could turn the unit off and on. The snap-in connecters seem to be tight with each other, but the receiving part, attached to the computer board, moves a tiny bit. The small wires leading into the male connecter were not loose. Could these (female?) connecters come loose from the board? If so, can I have them resoldered by someone?

 

Thanks, so much, for the procedure process. It helped keep my efforts organized and I believe I have found the problem. I took the whole scooter apart, including the controller. All the main cables were tested for continuity. I found that by moving the wires that run into the controller....the smaller ones, NOT the battery or other heavy cables....that I could turn the unit off and on. The snap-in connecters seem to be tight with each other, but the receiving part, attached to the computer board, moves a tiny bit. The small wires leading into the male connecter were not loose. Could these (female?) connecters come loose from the board? If so, can I have them resoldered by someone?

Yes, they can and depending on the nature of the fault you can do the job yourself. Sharp well lit photos of the board (both sides) with attention to showing the pins of the connector(s) clearly will help us assess the situation.

 

Yes, they can and depending on the nature of the fault you can do the job yourself. Sharp well lit photos of the board (both sides) with attention to showing the pins of the connector(s) clearly will help us assess the situation.

I have seen connectors where their solder joints look perfectly intact, but are not making contact. It pays to resolder them all.

 

I have seen connectors where their solder joints look perfectly intact, but are not making contact. It pays to resolder them all.

I agree, but I am mostly concerned about broken traces with require more skill to repair than reflowing.