Disable PTT stops TX, but still no RX

[Lionel Mesguen]

Hi,
I have just received the equipment from MarkerFabs (Hermes Lite 2, Filter Card, and IO Card).
I assembled everything without any difficulty, including soldering the 3-pin header and mounting the heatsink with the thermal pad.
The Hermes Lite board is properly detected on my LAN, and the antenna I am using works fine with another transceiver.
However, with Thetis HL2 (v2.10.3.12), as soon as I switch to RUN, the Hermes Lite goes into transmit, even though VAC1 and VAC2 are disabled and no VOX also.
If I enable Disable PTT, the unexpected transmit no longer occurs when I switch to RUN.
However, I do not understand why PTT was being triggered in the first place, because  nothing is connected to the Hermes Lite 2 except the antenna, the Ethernet cable and the 12 V power supply.
I removed the IO Card, but that did not change anything.
So at this point, it seems that some hardware PTT input may be active even though nothing external is connected.
I still have the other problem as well: I am still getting no receive at all. I also tested it with SDR Console, and there is no reception there either.
I also wanted to mention another point: in RUN / receive mode, the unit becomes relatively warm. In Thetis, I can see about 1.2 A current draw and around 55°C. This seems quite high to me for receive-only operation.
Could you please help me and let me know what procedure I should follow ?
Lionel - FG5EX

[brhl...@gmail.com]

in rcv its about 250mA and Temp 30 °C.Try without the enclosure and without heatsink. 

[Lionel Mesguen]

Hi,

For your information, I am getting back to you regarding the transmit issue that occurs as soon as I put the new Hermes Lite I received into RUN mode. 

I have now completed additional checks and the problem appears to be a reproducible hardware fault on the CW/PTT input of this new Hermes Lite 2.

Note: for the voltage the IO Board was removed.

With nothing connected to the CW/PTT jack:

    the HL2 enters transmit when RUN is enabled
    DB1 pin10 = 3.23 V
    DB1 pin12 = 0.84 V


According to the schematic, pin10 and pin12 should both be pulled up to 3.3 V. Pin12 is abnormally low, which explains the false TX triggering.

Lionel - FG5EX

[Pascal PBY]

Bonjour Lionel,

J'ai en moyenne 30 degrés en RX mais il vrai que la température ambiante n'est pas la même que chez vous. Par contre en RX j'ai 0 ampères, ça monte uniquement en TX...

73,

F6HCM, Pascal

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[Steve Haynal]

Hi Lionel,

What is the 3-pin header you soldered on?

At pin12 of DB1 with no power connected, what resistance do you measure between pin 12 and +3V3 and also between pin 12 and GND? This is to determine if the problem is an open to +3V3 or short to GND. You can find voltage measurement points here:

https://github.com/softerhardware/Hermes-Lite2/wiki/Hardware

73,

Steve

kf7o