I agree with Joe- the preamp may have gone west. Some power inserters
do use
a series resistor- but more often a choke. The only reason for it to burn
up would be excessive current draw by the preamp- or a kinked and shorted
feedline.
Put a VOM across the preamp input and see what the input resistance looks
like. Tantalums on the input often short when exposed a surge.

Dale W4OP
Dale W4OP
The only case I could see where it might be a resistor is if a MMIC like a
MAR-6 is the amplifier device. In that case calculating the resistor would
be easy per the device spec sheet. It doesn't look like Dressler has
published a schematic, so some reverse engineering might be in order.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

The resistive voltage divider/ isolator was fairly common in some of the LF
power inserters- Burhans et al:
http://members.shaw.ca/ve7sl/burhans.html

Dale W4OP