[hpsdr] Alex Interface Issue on Hermes

[dlwaddel at netzero.net]

I have a Hermes that energizes all filter relays on the attached Alex Tx board when power is applied. The relays stay energized until power is removed regardless of band selected in PowerSDR. Need help troubleshooting. Suggestions anyone? 

Background:
I have two Hermes systems: one connected to Alex and Munin that works great and that I have been using for several years, the second that I have been working on for several years that I want to connect to a 300 watt PA with its own filters.

The second Hermes seems to receive and transmit just fine when not connected to the PA. I have a Alex Tx board that I am using to check operation of the Alex interface before connecting the Hermes to the PA. The Alex Tx board operates correctly when connected to the operational Hermes system, so no problem with the Alex board.

I replaced U20, hoping that was the problem. This did not help. When I monitor the SPI_SCK on pin 4 of the Alex interface using an oscilloscope, the signal changes state right after power is applied to the Hermes, then stays unchanging. I would expect a pulse train for a clock signal.

SPI_DO on pin 3 of the Alex interface goes high when power is applied to Hermes and stays high. I would expect a pulse train for a serial data signal, at least for a short period of time initially and anytime the band is changed.

I do not see the SPI_CLK signal on pin 83 of U9 either.

The impression I get is that U9 is not generating the data and clock to send to the Alex interface. And yes, I have Alex selected in PowerSDR. :) Actually, I used the same instance of PowerSDR that I use on the operational Hermes system with all the same settings.

Don
K3DLW

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