Help testing Raleigh EVO Controller and cables (Motherboard) after water damage to plugs

[sapphire_ad]

Hi all,

I’m troubleshooting my Raleigh EVO electric bike, specifically the controller (motherboard). I’ve disconnected the components and need to test whether the controller is still functional, as I’m not getting power to the display. Here’s what I’ve done so far and what I need help with:

The battery is fully charged and functional (tested it brings 40v)

• I’ve disconnected the cables going from the motherboardto:
  • Display (5-pin: Red, Blue, Green, Yellow, Black — black is center pin)
  • Lights (2-pin: White and Brown)
  • PAS sensor (3-pin: Orange, Pink, Purple)
• Earlier, the display powered up when connected via USB to my laptop, but not when plugged into the controller.
• I found that the original plugs between display and controller were flooded/damaged, so I’ve replaced them and soldered new connections.
• Now, no power seems to come from the controller to the display, so I need to test voltages and check if the controller is dead or salvageable or some issue with cables.
  
  
  I tested continuity across the cables between motherboard plug and display plug and these are fine (after my soldering),
  
  but I’d like to know how to test and what to expect re. voltages if any:
  
  • Display (5-pin plug): Red, Blue, Green, Yellow, Black
    • I believe Red = +5V and Black = GND, but what about the others?
    • Should I see 5V between Red and Black when the battery is connected?
    • how to test separately display cable with no connection to battery - it is glued so no way to open it (unless I'm lucky to get it apart but would like to avoid it as a start)
  • PAS Sensor (3-pin): Orange (links to 3 cables on the motherboard end - potentially ground), Pink, Purple
    • What voltages or signals should I see while turning the crank?
    • Is one of these a 5V supply and the other a pulse signal?
    • how to thest PAS sensor itself without turning the crank
  • Motherboard - how to test it?
    • I have tested continuity against plug for motor but it looks like one end links to all on motherboar I assume due to multiple connections.
      
      Is there a safe way to test the controller output with the battery connected? Since the battery is 36V, I’m cautious about damaging anything or shorting components.

I have attached few photos. Any advice on expected voltages, safe testing methods, or tips for diagnosing a dead controller would be much appreciated!


Thanks in advance!

 

[saneagle]

40v fully charged is a bit low, and would indicate something wrong with the battery. It should be close to 42.0v.

If the LCD connector got drowned, you've probably wiped out the software in both the LCD.

Most Ebikes have:
red - battery voltage
blue - battery voltage return to power the controller when LCD is switched on
green - Tx or Rx
yellow - Rx or Tx
black - ground

You should check the voltage on the battery wires going into the controller to see if the connection is sound. The red going to the LCD is a direct branch from that, so should have the same voltage.

Your bike probably has the nightmare TranzX system, which is virtually impossible to diagnose as it uses comms to switch stuff on, but if you can get proper output voltage from the battery, probably best thing would be to chuck everything except the battery and motor, and get proprietary replacements. 40v might indicate that the battery is switched off. You need to put a load on it to see if it can provide any power.

 

[sapphire_ad]

After some testing, here’s where I’m at:

• All cables from the controller up to the display plug have continuity
• The battery is reading 41.2V after a full charge
• When the battery is connected, the display plug shows 41V–40.8V depending on pin combinations — but I’m seeing +/-40V between one pin and any other pin, which seems odd. Not sure if this is expected behavior?

Given this, I’m starting to think the display might be the issue, not the controller. Unfortunately, I don’t have another compatible display to test with. At this point I’m considering switching to a KT controller with LCD5, which might end up cheaper and faster than trying to hunt down a DP16 or DP27 display.

For context:

• The German manufacturer confirmed those displays are no longer in production
• Raleigh support claims availability might return by end of December 2025, which is… not helpful

Looking for advice:

1. Can I reuse my current motor and battery (36V geared hub, 250W, 12-magnet PAS sensor) with a KT controller setup?
2. Should I reuse existing cabling, or is it safer to replace it all when switching to KT?
3. Anyone tried opening one of these glued dp16/dp27 displays? The manufacturer said it can be done using heatgunand sharp tools, but there’s no guarantee it won’t break.

It’s turning into a bit of a nightmare, so any tips or shared experience would be massively appreciated!

 

[saneagle]

Ok so after testing:

- all cables up to the plug for display have continuity
- battery to board have 41.2V (after recharing)
- when battery connected - plug for display shows 41V or 40.8V depending on pin pairs but actually there is over +/- 40V on one pin plus any other pin - not sure if this is the way it should be?

That part sounds OK then. You should only measure voltage from ground (black) to any other pin, not from red downwards to any other pin.

The LCD works completely independently of everything else. If it has battery voltage on the red wire and is connected to ground on the black, it should switch on; however, some LCDs, controllers and batteries use comms to check that conditions are right to do their functions. The comms is handled by CPUs in the various devices, but if you connect battery voltage to either of the comms wires, it can wipe out the code in the CPU. What exactly happens when you press the power button on the LCD? Does it remain completely blank or does it flash on then off?

 

[sapphire_ad]

ok it make sense with wiping code in the CPU. when pressing LCD it remains completly blank no response.

 

[saneagle]

ok it make sense with wiping code in the CPU. when pressing LCD it remains completly blank no response.

The ones without the Tranzx system will switch on in that situation, but you can't change anything. Unfortunately, I don't know enough about how TranzX system works because I've never had one. I only know in principle, as it has the same sort of parts as any ebike.

 

[cyclebuddy]

• Earlier, the display powered up when connected via USB to my laptop, but not when plugged into the controller.

Probably because when your laptop is connected the display is getting 5v from the laptop USB to enable it to function. If you've now dried all your wet connections, have you tried reloading the bikes software, and leaving the USB lead connected to still provide that 5v then tested the bike to see if it works?

 

[sapphire_ad]

Ok, I think the case can be closed because the display is flooded.

All other connecions where just fine and display not really responsive, I took a hit and opened it (heat gun and sharp blade - no other metod) and capacitor flooded and motherboard too on one side.

Sound like I'm looking for alternative option for display and controller (back to square one ) . Unless anybody from the forum think of an alternative still

 

[saneagle]

Ok, I think the case can be closed because the display is flooded.

All other connecions where just fine and display not really responsive, I took a hit and opened it (heat gun and sharp blade - no other metod) and capacitor flooded and motherboard too on one side.

Sound like I'm looking for alternative option for display and controller (back to square one ) . Unless anybody from the forum think of an alternative still

Thanks for the update. That looks pretty bad. I'm still not sure about your battery. In particular whether it needs the comms to stay switched on. Unless somebody can give you a definitive answer, you really need to do a load test. You should connect anything that will draw something like 1A or more to see if the battery will stay on for more than ten minutes. If it does, you can use any controller you want. I prefer KT sinewave controllers because of the pedal assist functions they have. If it doesn't, you can start crying, though there are still solutions. You can buy any KT LCD except LCD1, and it's a good idea to buy the throttle, speed sensor and pedal sensor as well because they don't cost much if you get them as a package, and it saves all the messing about with compatibility and connectors.