[hpsdr] Tapr hombrew hermes shutdown problem

[Phil Harman]

Hi Oliver,

Check F3, on early BOMs it was 1A but was increased to 2A on later versions.

73 Phil..VK6APH




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>
> Hi All !
>
> I am having a problem since sunday. I am not making progress in debugging
> the error. Hermes ran nearly the whole weekend during the contest. The
> enclosure was warm but not hot.
>
> The problem:
>
> The board starts fine es every time and i can run it for lets say  one
> minute with cuSDR64, ghpsdr3. After the minute the leds are only showing
> half of the light than before. the board is then no more reachable and
> cannot be discovered. When i start the board  in bootloader mode
> everything
> is normal. When i remove the jumper and powercycle the board it runs also
> fine just to the time i put the networkcable in. it seems that network
> traffic can speed up that failure.
>
> I measured as follows:
>
> U18, PIN3 = 13,6 Volt
> U18, PIN2 = 11,9 Volt
>
> in normal operation and after shutdown.
>
> The SMPS 5V output shows 4,96 V also in normal conditions and after the
> shutdown (measured at L32). So i think the 12V and 5V Buses are ok ?!
>
> Now i measured at C153 and C174 and the input Pin of the LTC1529. During
> the normal operation i have 4,45 Volt there. During the minute until the
> shutdown the Voltage decreases down to 2,83 Volt in 0,01 Volt steps. The
> last steps are faster.
>
> When i understand the schematics right i should have the same voltage at
> the end of L32 and at C153.
>
> This must be something serious or silly. I hope the last one.
>
> In bootloader mode i am able to program and successfully reprogrammed the
> board back to 2.2 which results in the same behaviour.
>
> 73 Oliver DL6KBG
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