Looked at photo diode forward voltage for ETMY ACB per LIGO-T1100637. PD forward voltage(≈ 0.5V) Pin 13 & 12 PD forward voltage: 0.428V Pin 10 & 9 PD forward voltage: 0.421V Pin 7 & 6 PD forward voltage: 0.428V Pin 4 & 3 PD forward voltage: 0.421V Filiberto Clara & Mitchell