Dawes Swift

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
Are there any tests that I can do on the wiring in and out of the control unit to verify if the display unit and handlebar controller are faulty?
Only if you have the flat type connectors. If it's the cylindrical sealed ones, it's no.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
You didn't say whether that flat connector is connected to the LCD or the motor. It looks suspiciously like the motor one because the blue is normally next to the red for LCDs.

If connected to the LCD:

Pull out the hot melt glue from the back of the connectors. It doesn't do anything anyway. With the battery switched on and the connector connected, stuff your probes up the back of the red and black wires on the LCD side of the connector to measure the voltage. You should see battery voltage. Keep your probes there and hold down the power button on the LCD and see if anything happens to the voltage.

Next, stuff your probes up the back of the blue and black wires. You should see 0v. Keep the probes there while you press and hold the power button, and see if anything changes.

Are you sure that the silver bit of the LCD doesn't unclip from the black bit? They look separate in your photo.
 
Last edited:

DJG

Pedelecer
Jun 27, 2020
26
1
You didn't say whether that flat connector is connected to the LCD or the motor. It looks suspiciously like the motor one because the blue is normally next to the red for LCDs.

If connected to the LCD:

Pull out the hot melt glue from the back of the connectors. It doesn't do anything anyway. With the battery switched on and the connector connected, stuff your probes up the back of the red and black wires on the LCD side of the connector to measure the voltage. You should see battery voltage. Keep your probes there and hold down the power button on the LCD and see if anything happens to the voltage.

Next, stuff your probes up the back of the blue and black wires. You should see 0v. Keep the probes there while you press and hold the power button, and see if anything changes.

Are you sure that the silver bit of the LCD doesn't unclip from the black bit? They look separate in your photo.
 

DJG

Pedelecer
Jun 27, 2020
26
1
You didn't say whether that flat connector is connected to the LCD or the motor. It looks suspiciously like the motor one because the blue is normally next to the red for LCDs.

If connected to the LCD:

Pull out the hot melt glue from the back of the connectors. It doesn't do anything anyway. With the battery switched on and the connector connected, stuff your probes up the back of the red and black wires on the LCD side of the connector to measure the voltage. You should see battery voltage. Keep your probes there and hold down the power button on the LCD and see if anything happens to the voltage.

Next, stuff your probes up the back of the blue and black wires. You should see 0v. Keep the probes there while you press and hold the power button, and see if anything changes.

Are you sure that the silver bit of the LCD doesn't unclip from the black bit? They look separate in your photo.
The flat connector does go to the LCD, voltage between red and black is 41.3v and the same when the power button is pressed.
Voltage between the black and blue wires is 0v and the same when the power button is pressed.
The silver part of the LCD appears to be crimped over the black plastic but I could have another closer look at it.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
You might be able to get some basic function from your bike if you disconnect the LCD and bridge the red to the blue and the green to the yellow. That should show that the motor and controller are working. If it sparks when you bridge the red and blue, it could mean that there's a short in the controller that took out the LCD, so be careful.

You bike's electrics are fairly standard. You can replace the controller and LCD for better ones for about £70, which might be cheaper than just your special LCD. That would require a bit of wiring. Also, I have 80% confidence that you could use any Bigstone LCD as a replacement. The only problem is we don't know whether the problem is solely in the LCD or caused by something like a short downstream to the blue wire, which would blow the transistor that switches it on.
 

DJG

Pedelecer
Jun 27, 2020
26
1
You might be able to get some basic function from your bike if you disconnect the LCD and bridge the red to the blue and the green to the yellow. That should show that the motor and controller are working. If it sparks when you bridge the red and blue, it could mean that there's a short in the controller that took out the LCD, so be careful.

You bike's electrics are fairly standard. You can replace the controller and LCD for better ones for about £70, which might be cheaper than just your special LCD. That would require a bit of wiring. Also, I have 80% confidence that you could use any Bigstone LCD as a replacement. The only problem is we don't know whether the problem is solely in the LCD or caused by something like a short downstream to the blue wire, which would blow the transistor that switches it on.
I have disconnected the flat connector to the LCD and shorted the red to the blue on the controller side and the green to the yellow, no sparks , tried riding the bike and got no power assist.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
With the red and blue bridged, measure the voltage between the red and black PAS wires. 5V tells you that the controller is switched on and should be working.

Don't worry, by measuring and testing, we will be able to get to the root of your problem. If I had your bike in front of me I'd have the answer in minutes, but when we do it remotely, we have to go through an iterative process.
 

DJG

Pedelecer
Jun 27, 2020
26
1
With the red and blue bridged, measure the voltage between the red and black PAS wires. 5V tells you that the controller is switched on and should be working.

Don't worry, by measuring and testing, we will be able to get to the root of your problem. If I had your bike in front of me I'd have the answer in minutes, but when we do it remotely, we have to go through an iterative process.
The voltage is 2.1v
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
The voltage is 2.1v
It's good that you got something, but it seems a bit low. This 5v is independent of the LCD and battery voltage, so we need to confirm it before going any further. If your bike has a throttle, check between its red and black, otherwise we have to go for the motor connector. Disconnect the motor and put your black probe on any ground. I normally stuff it inside the insulation sleeve of the bullet connector at the controller to leave my hands free. Get a needle and stick it in each of the small holes in the connector in turn and measure the voltage on it. One should be 5v. There might be voltage on three of the others depending on how the controller is configured. Please report what you find.

Assuming that you get the same 2.1v, you're going to need a new controller and display. We can guide you on that after the above test, assuming that you can do it. They're not at all expensive. A direct replacement is about £30 or you can make an opportunity out of a crisis and improve your bike massively for about £70.
 

DJG

Pedelecer
Jun 27, 2020
26
1
It's good that you got something, but it seems a bit low. This 5v is independent of the LCD and battery voltage, so we need to confirm it before going any further. If your bike has a throttle, check between its red and black, otherwise we have to go for the motor connector. Disconnect the motor and put your black probe on any ground. I normally stuff it inside the insulation sleeve of the bullet connector at the controller to leave my hands free. Get a needle and stick it in each of the small holes in the connector in turn and measure the voltage on it. One should be 5v. There might be voltage on three of the others depending on how the controller is configured. Please report what you find.

Assuming that you get the same 2.1v, you're going to need a new controller and display. We can guide you on that after the above test, assuming that you can do it. They're not at all expensive. A direct replacement is about £30 or you can make an opportunity out of a crisis and improve your bike massively for about £70.
I left the link wire between the red and blue and checked all the terminals on the motor connector, I got a voltage on 3 of the terminals, 1.1v, 1.1v and 1.7v. Photo of the connector that I checked.
 

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vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
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Basildon
OK. it's looking like something is wrong with both your controller and control panel. The root cause could be in either or both. There's a very small risk that the pedal sensor and motor hall sensors are damaged too.

Some final questions before deciding what to do:
Where do you live?
Are you OK with wiring and soldering?
How much do you want to spend vis-a-vis what I said in my previous post
 

DJG

Pedelecer
Jun 27, 2020
26
1
OK. it's looking like something is wrong with both your controller and control panel. The root cause could be in either or both. There's a very small risk that the pedal sensor and motor hall sensors are damaged too.

Some final questions before deciding what to do:
Where do you live?
Are you OK with wiring and soldering?
How much do you want to spend vis-a-vis what I said in my previous post
I live on the Isle of Wight and am ok with soldering and wiring, as for the price of parts, I don't want cheap parts that may break down again but don't want to spend more than I need to as it's a commuter bike.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
I live on the Isle of Wight and am ok with soldering and wiring, as for the price of parts, I don't want cheap parts that may break down again but don't want to spend more than I need to as it's a commuter bike.
OK. I'll post in the morning. i want to think about a couple of ideas.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
I'm trying to modify a spare Freego controller, so that you can use it to test your motor. I'm worried that your motor's hall sensors are damaged. It's only a small chance, so nothing to worry about, but it affects the choice of controller to sort you out. I don't want you to end up with a sensorless controller when your motor halls are OK because they're not as good, and if you get a sensor controller and find out the motor halls are no good, you've wasted your money.

I should have an answer whether it works tomorrow.
 
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DJG

Pedelecer
Jun 27, 2020
26
1
I'm trying to modify a spare Freego controller, so that you can use it to test your motor. I'm worried that your motor's hall sensors are damaged. It's only a small chance, so nothing to worry about, but it affects the choice of controller to sort you out. I don't want you to end up with a sensorless controller when your motor halls are OK because they're not as good, and if you get a sensor controller and find out the motor halls are no good, you've wasted your money.

I should have an answer whether it works tomorrow.
Many thanks really appreciate the help.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
Many thanks really appreciate the help.
I'm still working on it. I lost my glasses Friday afternoon and I don't have any spares. I found them this morning in my bird seed trunk.

When I'm looking at things in the range of about 3ft, I can see the same with or without them, and when I look down, they sometimes fall off. In this case they fell off while I was shifting bags of seed around in the trunk and I didn't notice. Immediately before that, I had been searching for connectors and controllers in my many sheds and other stored parts around my house, and I thought I might have taken them off to inspect something because I can't see close up with them. I spent a lot of time on Friday night and Saturday morning looking for them, but without them, I couldn't see well enough to search properly. I had previously looked in the bird seed trunk, but I didn't see them., but this morning, when I fed the birds, I pulled everything out and there they were at the bottom.

Unfortunately, I'm busy for the next couple of days because the Welsh government has finally opened the boarder and allowed the harbour to put my boat back in the water, so I have to go and prepare it in time for the craning in on Friday.

I might have time tonight to do something. I have the parts I need now, I've just got to do some soldering. I'll let you know if it's successful.
 

Gavin

Pedelecer
May 11, 2020
243
125
A life of bikes, boats and birds eh VFR....you're making the rest of us jealous :D
 

DJG

Pedelecer
Jun 27, 2020
26
1
I'm still working on it. I lost my glasses Friday afternoon and I don't have any spares. I found them this morning in my bird seed trunk.

When I'm looking at things in the range of about 3ft, I can see the same with or without them, and when I look down, they sometimes fall off. In this case they fell off while I was shifting bags of seed around in the trunk and I didn't notice. Immediately before that, I had been searching for connectors and controllers in my many sheds and other stored parts around my house, and I thought I might have taken them off to inspect something because I can't see close up with them. I spent a lot of time on Friday night and Saturday morning looking for them, but without them, I couldn't see well enough to search properly. I had previously looked in the bird seed trunk, but I didn't see them., but this morning, when I fed the birds, I pulled everything out and there they were at the bottom.

Unfortunately, I'm busy for the next couple of days because the Welsh government has finally opened the boarder and allowed the harbour to put my boat back in the water, so I have to go and prepare it in time for the craning in on Friday.

I might have time tonight to do something. I have the parts I need now, I've just got to do some soldering. I'll let you know if it's successful.
No problem, I've been trying to get my motorbike to run smoothly for almost a year and finally acheived it this weekend so have had plenty to do.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,877
1,755
Basildon
No problem, I've been trying to get my motorbike to run smoothly for almost a year and finally acheived it this weekend so have had plenty to do.
Let me guess. Hmmmmm! I think I can see it in my mind's eye. It's a BSA B25 SS 1971.
 

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