very good manual, with detail and clarity in esquematic diagrams and waveforms .
Text excerpt from page 5 (click to view)
Precaution to replace Optical block (SF-P101NR)
Body or clothes electrostatic potential could ruin laser diode in the optical block. Be sure ground body and workbench, and use care the clothes do not touch the diode. 1) After the connection, remove solder shown in the right figure.