I have made the same modification to the Yarm trans PD whitening board as was done for the xend, to increase our SNR. I put in a 2.1kOhm thin film resistor in the Rgain place.
When I was pulling the board, the ribbon cable that goes to the ADC had its connector break. I redid the ribbon connector before putting the board back.
I see signals coming into the digital system for both the high gain and low gain Y transmission PDs, so I think we're back. I will re-do the normalization after Jamie is finished working on the computers for the day.