Yeah, the soldering is bad, dry flux all over, solder blobs , bridging.
I have already cleaned it with IPA now and using soft brush knocked off all of the solder balls and that seems to have fixed most of the display but some items still dont display.
Am not worried about the existing code, once i find out the mcu it will be my next job to figure out a way of dumping it, I already have ways into pic 8's, stm8/stm32s , qualcomm chips to dump the flash and writing code for a simple dash display is no biggy either, would be fun actually to hide easter eggs in there.
The device has only one button for changing display of trip/odometer and my boot up hold button down tests have given me what maybe a service menu but with some of the display not working it's hard to tell. The replacement does not trigger in this way on the bike, it seems there has to be a additional B+ signal that my bike loom does not have but my bench loom does.
Currently waiting some more solder braid so i can clean up the excess solder and then run the fat tip over all the legs with some quality liquid flux then a quick IPA bath
Oh thanks for pointing out my date typo, have corrected the original now.
Speed sensor is hall effect, the factory sensor is all in one unit encased on the wheel strut with a magnet on the rim , its a 5v type so ground, 5v+ and signal, I actually got a extra one with the Hawk 250 replacement so i will be able to test the speedo with a card wheel+drill on my desk or grab a 5v arduino for a false signal generator.
One of my concerns was ensuring the odometer is correct as i take my service schedules serious , my father was a mechanic and drilled it into me to service regular. as so far it seems the prior owner and service center just went "meh a zero value is fine, done less riding right ? " but thankfully i had photo's of odometer just before each one failed so i have a within 500km figure.
I think tonight i will sped time on github looking for mcu schematics that use these pins as well as test what type of IO that programming port is, 2 wire says to me SWD or plain UART or a rare case of jtag over swd. None of my usual chineese tech sites that disassemble stuff have featured these boards (quite common over there on their bikes, just watch any bike video and you will see loads)
darkspr1te