Faulty KONNWEI / MAXISCAN dongle

This page describes problems we’ve seen or had reported with the KONNWEI dongles we recommend.


Batch of faulty terminated dongles (new hardware design)

There is a recent (2nd half of 2017) batch of KONNWEI902s that at least have a problem with the termination resistor. We are still investigating this, as the entire hardware has changed and we’re not sure yet if fixing this solves another major issue. We will update this section and the blog as soon as we know more. See http://canze.fisch.lu/dongle-trouble-3/


Short circuit on the crystal (original design)

I you happen to have a faulty KONNWEI KW902 dongle, of course our first advice would be to ask for a new one. Having said that, we recognize sometimes this not possible, or the time span involved is too inconvenient. If you happen to be an electronics enthusiast, this post might help you fixing a problem we’ve seen before. Have a look at this picture, especially the black tube starting at the right edge of the largest white connector.


The tube is a piece of heat shrink tube over a small metal cylinder crystal. You can see the metal cap just popping out at the right side. The crystal occupies maybe just the right one third of the heat shrink tube. The wires going to the PCB are very long and not individually insulated. A short is VERY easily made. If this happens the dongle is usually dead, but it might still connect to Bluetooth. This confuses CanZE as there is and there is not a dongle.

The repair is pretty easy.

  • Carefully cut away the shrink wrap with  sharp knife.
  • Ensure the two wires are not shorted out, i.e. by inserting a piece of paper between them. Be careful not to dislodge the two wires from the PCB.
  • Secure the crystal, wires and paper with a drop of glue. Heat gun glue will do fine. Double check no metal parts or wires touch.