Hi Eric, I'm voting with my friend Dave, K1WHS, for looking first at the voltage regulators.
The 8 volt regulator supplies the TC4427 gate driver IC, which in turn provides 7R/7T voltages separately to the Transmit and Receive switching circuits. The loss of the 7R/7T voltages would disable the PIN diode T/R switches and render the radio deaf and unable to transmit. If the 8 volt regulator doesn't collapse after some time observing its output voltage, I would check the TC4427 (U11 on the RF Board) to be sure its outputs are correct (the 7R/7T voltages). The regulator is likely the first culprit - its '8A' output pin provides power to a large number of circuits in the radio. 73, Mike, K8CN ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
