Replacement preamp for shure mx418 microphone

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Hi,

I've got a dead shure mx418 gooseneck mic on hand. The capsule is good (checked on another mic) and the wires too. So it's probably the preamp that died.

What kind of preamp does such a capsule (shure rb185) ? According to the datasheet, it's an electret condenser. http://cdn.shure.com/specification_sheet/upload/52/us_pro_mx412s_418s_specsheet.pdf

I don't need to replace it by such a small pcb but it needs to be phantom powered.

Thanks for any help.
 

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Thanks :up: The schematic has been dropped from the 2006 revision of the user manual.

edit: the pcb was completely redesigned it seems, it's going to be a detective work... Worst case is that I can now adapt ESP project 93 to the shure mic based on that schematic.
 
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Fixed. 🙂 A big "thank you" again for finding that schematic.

It was the input fuses that blew (I cannot see those on the schematic, they must a last revision's addition). Blew so completely in fact that there wasn't anything left but the tracks. I soldered small wires from the xlr input pins to the l3/l4 inductors and everything works perfectly.

Weird... I still wonder what happened to these fuses.
 
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