Jose wrote: > I?d like to repair a HP58504A antenna that don?t deliver any output > signal. The current is about 30 mA ( I think too high), and the > transistor (unknown type) and the MMIC (uPC2749TB), seems to be with > correct voltage. > > Does anyone have any experience or data about this antenna? > > I took an inside photo: http://www.ea1px.es/HP58504A.jpg Can the > transistor be identified by the color code?
I'm assuming correctly that the big blob of solder in the LL is the antenna connection, otherwise please ignore all of this. I suspect that "transistor" is really an MMIC in one of the fancier packages rather than a discrete transistor. It looks to me as if the bias flows through the trace on the BR and then through a couple of 001 R's before the bias setting 221 R. This MMIC is before the filter, so it is probably been selected and biased to avoid IM problems. But I don't think 30 mA sounds too high. -ch _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
