Howdy all,
For some time now my Mirage A-1015-G 6M amp has been having problems with
its internal preamp. If I turn the preamp on, my RX noise level goes way
up and if there are any stations on the band they get wiped out. It
definitely does not help and seems more like a big attenuator than
anything else.
So tonight I opened up the unit and found the preamp transistor. I have
no schematic of the unit, but I believe under power the gate of the
transistor has about 3.5 Volts on it. The drain has zero volts (actually
there is a voltage but it is in the millivolt range).
I believe I have the Drain and Gate picked correctly because for one I am
familiar with how ceramic micro-x parts are marked and secondly, when
turned off, the path from the drain to the transmitter port on the amp is
an open circuit and when turned on, it is a short circuit.
Anyhow, without a schematic I am unable to determine fully where my
problem might be, wether or not it is a bad FET or if some other
component has failed in the drain bias circuitry.
Anyone got any ideas?
Thanks es 73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na <--- CHECK IT OUT! It's been updated!!!!!
"A life lived in fear is a life half lived."
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