BBSO2 display bad? Need help!

[RandyFrank]

I have the Bafang BBS02b. I've got about 3000 miles on it, its been very reliable. Finally getting around to changing the PAS levels so that:
PAS 1: just enough assist so that it's like a super lightweight bicycle. Because of motor drag it's very hard to pedal with no motor assist
PAS 3: where the original PAS 1 was, this gets me to 18-20mph
PAS 5: 100% power

I was trying the limitless .el Profiles, and had pulled apart the cable from the motor to the display maybe 8-10 times total, and hooked up to my Win11 laptop using Penhoff's modified Calibration tool. I successfully changed and saved the Profile several times.

After my 3d attempt, when I put it all back together, the display was dead! HOWEVER, with the programming cable hooked up from the bike to the laptop, I was able to Read and Write the Flash memory, and a small LED that blinks when the power is on was blinking (the shift interrupt), both of these things makes me think that everything is OK but the display is not reading for some reason.

Display and overall troubleshooting: I'm not much of a mechanical or electrical guy so these are my best uneducated guesses.
1. These control cables are probably made from super thin wire and after unplugging and plugging back in I might have damaged the cable to the display?
2. The display itself is kaput?

My only thoughts so far:
1. Extensive research
2. Buy a new display that has a return policy to see if that's the problem
3. Pull open the display and look around, but this seems unlikely


As you can imagine I've been very upset about this. I'd love to buy a new bike or take it to a shop and have someone fix it, but I live on a very very limited fixed income, so having my main means of transportation go out on me is really rough. Help to diagnose this problem would be much appreciated!

Randy

 

[amberwolf]

The display is powered from the battery voltage supplied by the controller. It then supplies that back to the controller to turn it on when you use the power button.

Does your system power on and operate, but just the display doesn't show anything? Or does it not turn on at all or work?


If it's the latter, then the display itself is probably failed internally at the LCD or driver chip that runs the LCD.

If it's the former, then it's probably a bad connection in the display connector or cable, anywhere from the controller to the display.

One side of the connector will have pins that stick out, and the other barrels for the pins to go into that act as spring clamps onto the pins. If the barrels spread out, they wont' make good contact; the most likely pins for this in your case are the main B+ (P+) and Ground (GND). The pins can also be bent over flat...if that happens they will probably break off when straightened.




If it's just a cable failure, and you're willing to splice wires, you can buy a Higo extension for that cable, cut it in half, and replace whichever side has failed by splicing this in place of that. Or do both sides if you find it necessary.

 

[docw009]

I believe you can ride the bike with the programming cable plugged in, and the USB end not connected. Throttle works and you get a default PAS, which may not suit you, but better than no bike.

I haven't done it using the program cable, but I have done it by setting a jumper between the brown and orange pin, which the program cable also does. I did ride the bike around the block when I tried it a few years ago.

But I would suggest doing what AW said, and check that the pins are straight first.