Good work on the button issue - Grin will be able to get you replacement parts. Now the new matter:
The power reading is derived from the voltage and current readings, so the underlying cause is a bad current measurement which incidentally throws off the Watts display.
There are three primary sources of difficulty that will lead to the bogus current readings:
- bad shunt configuration
- RShunt and/or hi/lo range settings
- bad shunt connection
- CA_DP plug not seated properly,
- bad wire connections to the two mating CA-DP connectors,
- bad solder joint from CA-DP cable to CA PCB,
- bad solder connection to shunt in controller
- failure to Zero the Amps in Setup
- although this appears as a 'configuration' problem, it is affected by hardware changes and so sometimes needs to be revisited.
So - since your CA was working and your shunt hasn't changed, item (1) seems unlikely - and to a lesser extent item (3).
You did just mess with the hardware, so item (2) looks like the culprit - and to a lesser extent item (3).
I recommend disconnecting and re-seating the CA_DP connector a few times to address (2a). Don't scrape or sand the contacts (it will remove the tin plating that gives corrosion resistance) - they will clean themselves just by being inserted. Chances are this will fix things up.
After that, you can go down the list in (2). Check the CA-DP connections to the conectors and the PCB to make sure that all wires are soldered and not just hanging on by a strand. Since you were just in the CA, this is an area of interest. If you have a multimeter, you can test continuity of the blue and white shunt wires from the CA-DP connector contacts to the solder pads on the PCB (S- and S+). The manual shows the pin numbers and has an illustration of the PCB.
You can always Zero the Amps again, but although although this may cure the symptom by correcting the ZERO display, the readings may not track correctly and the underlying problem that is fouling up the shunt measurement will remain. Still, this is easy to do and you can repeat as required as your investigations correct the real problem.
As always, contacting the vendor is the best plan - you already paid for excellent Grin Tech Support with your unit - use it.
