I’m restoring a Roland D10 and every time I change a patch I get the display showing “check internal battery”. However, even after replacing the battery for a new one the same message keeps occuring. Any ideas? - Darren.
It looks like the Vref voltage line is not giving out a nominal 5V but about 0.2V, I suspect the electrolytic capacitor C92 (4.7uF/25V), which appears to smooth the output. This gives the voltage comparator a false battery low warning even though it is brand new. This would also affect the VALUE slider and the bender pot (left-right motion) too.
This will affect other Roland D-xx series too, including the D-50 although probably a different capacitor label.