Schematic for Echostar AD3000ip LNB switching circuit

Llew

I've been poking around in the AD3000ip to check out the layout of the LNB switching supply, as I have in the past had failures of a couple transistors due to silly shorts brought on by failure to make sure the cabling from LNB to f- plug is sound (I'm always swopping and re-terminating connections).

Q904 and Q909 are in my opinion the most likely suspects to be damaged if a short in the cable occurs for any length of time.

Here's my effort at drawing the schematic. I haven't provided values for the semis, just swop like for like or use any medium power rated transistors.

Llew

Attached Thumbnails

 

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Burnham Beech

Thanks for the information. Have copied it for future reference if needed.

Llew

Always worth trying to keep the old box working - (within its limitations, channel capacity etc). But then I only really use it for dish positioning.

Later receivers than this Echostar have a dedicated LNB switching chip that provides the H/V voltages; this one just uses basic easily available or substitute components.

I couldn't at first work out how the 12V regulator U901 was able to supply the 13/18V to the LNB, as what is normally the ground terminal fixes the output at 12V.

In this circuit this terminal is raised through Q909 to 1V or 6V, which will give 12V+1V=13V or 12V+6V=18V to the LNB.

I was thrown by the fact that the fault I had (shorted Q909) earthed the ground terminal of U901!

Llew

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KONAMI

Good Morning Can I have a complete Echostar Ad 3000 IP circuit diagram with a list of all coponents use ? I am sur that you can help Tanks.

Llew

Nothing available that I'm aware of except for the power supply posted on this forum. Sorry.

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