Hi!
Just built my two Rev Ds. (actually these are the third and fourth I've built over the years).
First unit worked perfectly, calibrated perfectly, straight away.
Second unit, everything fine during calibration until the bit where you repeat the four steps. When GR Off is engaged, nothing changes - the AC output doesn't change regardless of where the switch is positioned..
Any ideas? I've been through and re-flowed all the solder joins on the meter board, but I haven't gone over the resistors yet... dreading that part. It's pretty tidy. I'll add a photo. Can you see any issues?
Thanks!