We have a 528 with photo spectrometer and a 528 that is just a densitometer. The expensive one with the photo spectrometer keeps saying check battery. We bought new ones for both xrites and even with the charger plugged in we keep getting this message and it will not do the reading. Xrite wants almost $700 to basically refurbash it. Anybody know either where I can get a schematic for this or someone who is more reasonably priced who can look at it. Money is tight. This is a $3000 unit but changing a diode for $700 sounds extreme. We have tried doing a battery swap and that is not the fix. I am going to take it apart this weekend and take a peak. Hopefully it is just a bad wire or a simple voltage regulator shot.