Hello Elecrafters:
I'm looking for some troubleshooting help, please.
This morning on our local 6 meter CW sked, I was barely able to hear guys
that are usually very strong signals. Opening up the transverter, I
discovered that I am unable to adjust the LNA Bias Adjustment(R13)for Q3 to
the required 200 - 275 mV. It adjusts from a low of about 4 mV up to 55 mV.
I've got 13.7 V at 12R, 3.74 V at the R12/R15 junction, and 0.650 V on the
drain of Q3. Current coming down that leg is 55 mA based on voltage drops
across R12 and R15. With 55mV (TP2) drop across R14, a current of through
R14 of about 12 mA is indicated. I think this means that Q3 (or something
else) is sinking about 43 mA (55 mA - 12 mA). (If my memory of Mr Kirkoff's
laws are intact).
My question is: Has Q3 has bit the dust?
Thanks...
73,
Ken Wagner K3IU
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