The charging problem is a simple design flaw - how to fix it
Having had the same problem as a lot of people (Rider 2 not charging), I decided I should have a go at fixing it as I don’t have time to wait for a replacement or even for one if I buy because I need my bike every day.
Checking voltages, I have 12V at the connector to the mount (pushed wire in to be able to get the multimeter on it). But only about 1V at the gold pins (it seems the outer pins are the ones of interest). As it says on the mount, there should be 5V at this point. As it has 12V in and 5V out with no evidence of a heatsink to disperse the 14W that will be lost by a simple voltage regulator, I have to assume something more complex in side.
Taking the unit to bits is easy (saw through one of the pins that the contact plate tilts on), will be able to knock the pin out and replace with a new one made from anything the right size. Undo the 4 x screws and there you have a small circuit board (I was right that it’s not a simple voltage regulator).
No sign of anything obvious, so time to put some volts on the board. Feeding 12V to it, I still have only 1V on the gold pin. However, on the other side of the board where the gold pins are soldered to the board, I have 5V. This suggests the problem is in the spring loaded contact pin… but what can go wrong, it’s gold plated so even if water got in, it would still work. Carefully removing the black plastic pin holder (no need to undo the solder for the pins, they aren’t physically connected, the black plastic holder is simply glued in place with a rubber silicon type compound. Use a sharp knife to cut through the silicon then a screw driver to lift the mount. Be ready for the pins dropping out, do it over a clean surface and fairly close to stop the pins bouncing away should they fall.
Once removed, I found the design flaw. Like I said, the pins are gold plated, so are the bits the pins slide in and out of. However, guess what the springs are made of… the springs that push the gold pins up to make contact with the pads on the bottom of the Rider. STEEL!!!!! And what happens to steel when it gets wet??? And how good an insulator is rust? Very good! Well, good enough to drop 5V down to 1V.
Good thing the contacts are gold plated, the rust doesn’t stick too well to gold, a rub and it’s gone. But what do I do about the spring that’s no good any more? I haven’t got one that size to hand… I guess I could use one from one of the middle two contacts (not sure what they are for). Putting it all back together, remembering to seal the plastic contact holder because the contacts themselves are not sealed. Screw the case together and try it out. IT’S WORKING, I just saved myself 50 quid! Only thing I haven’t thought of yet is the pin I put the saw through. Hmm, found a nice nail about the right size. Cut it to length, pushed it in and used some epoxy to make sure it won’t fall out.
People seem to be scared to try and fix things these days, maybe because they don’t understand electronics. I guess I’m lucky that I was trained in electronics, so have a reasonable understanding, but last time I designed a circuit was about 12 years ago. Things have changed a lot in that time and I doubt I would have tried to do any more if the fault was in the circuit. At the end of the day, I had nothing to loose and with the problem being a simple mechanical connection problem it was an easy fix. If it’s not charging and there’s no chance of you getting a freebie from TomTom, give it a go!
