[hpsdr] Tapr hombrew hermes shutdown problem

[Oliver Goldenstein]

I read more about the PTC Fuses and i checked my ordered fuses.

they are all MF-MSMF110/16 which have a holding current of 1.10 Ampere and
a trip current of 2.20 Ampere.

Phil is it right. that the fuse must have a hold current of 2 Ampere?

73 Oliver DL6KBG
Am 19.02.2013 08:55 schrieb "Oliver Goldenstein" <
oliver.goldenstein at gmail.com>:

> Many thanks Phil! Shame on me. The first time i read about multifuses and
> i always checked for continiuty. Oh man. But good to know.
>
> The rest of the wonder is why the setup worked before.
>
> 73 Oliver DL6 KBG
> Am 19.02.2013 08:38 schrieb "Phil Harman" <phil at pharman.org>:
>
>> 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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