[hpsdr] Tapr hombrew hermes shutdown problem

[Phil Harman]

Hi Oliver,

The current from the 13.8v supply at 0.7A is about right.  The current
from a 5v supply will be higher since you use the current advantage of the
SMPSU. But the power drawn will be much the same i.e.

13.8v x 0.7A   = 9.66W

5v x 1.93A      = 9.66W

I'm sure you will find with the 2A fuse all will be well.

73 Phil....


> Hi Phil !
>
> You are right. The BOM says 2 A but i checked what i have ordered and they
> are 1.10 A.
>
> U did another test this morning powering rhe 5 V Bus from an external
> power
> supply.
>
> The voltage on the power supply decreased to 3.8 Volt 1.4 A!
>
> With powering from one 13.8 Voltvpower supply  i have around 0.7 to 0.8 A.
> And after the shutdown 0.3 A.
>
> I am confused.
>
> 73 Oliver
> Am 19.02.2013 06:47 schrieb "Oliver Goldenstein" <
> oliver.goldenstein at gmail.com>:
>
>> Hi Phil !
>>
>> The Fuses are the 2 A ones and they are ok.
>>
>> 73 Oliver DL6KBG
>> Am 19.02.2013 02:07 schrieb "Phil Harman" <phil at pharman.org>:
>>
>>> Hi Oliver,
>>>
>>> Check F3, on early BOMs it was 1A but was increased to 2A on later
>>> versions.
>>>
>>> 73 Phil..VK6APH
>>>
>>>
>>>
>>>
>>> > ***** High Performance Software Defined Radio Discussion List *****
>>> >
>>> > 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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>>>
>>>
>



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