Good product. All the information is invcluded, but due to the complexity of the amplifier, it still is difficult to get it to operation again.
Text excerpt from page 4 (click to view)
Precaution to replace Optical block (KSM-213RSCM) (KSS-213R)
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.