Golden Media 202 Modification for external LO

This procedure is applicable for twin LNBs of type Golden Media. DC supply and intermediate frequency routed via one connector, the LO reference fed via second connector. The modification is outlined in the below schematics:

mod_lnb.pdf

Procedure:

  • Open LNB (remove silicon sealant)
  • Power LNB with 12V and probe oscillator (can also be on the opposite PCB site) with scope and find pin that shows highest level
  • Remove oscillator and Cs which are at the pin with highest level (hot air gun or 2 soldering irons)
  • Remove PCB-L at LO connector and C to mixer.
  • Freely position Rs and Cs from LO connector to free oscillator pad. Depending on LNB version different routings are necessary. Use tape to isolate PCB tracks
  • Remove PCB-L from intermediate frequency connector and replace by 2.2-4.7µH ferrit bead. Make sure ferrit bead resonance frequency is far away from 400-800MHz
  • Test with external power supply and LO. Current consumption 100-120mA