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Re: [N8VEM: 15625]

Thanks Douglas! I will keep this in mind and keep on debugging until I find the problem.

Op maandag 18 februari 2013 09:55:56 UTC+1 schreef douglas_goodall het volgende:
Ronald,

Don't despair, we have all been through this, and when you have found
the last of the troubles
and you have a working board, you can join the part of the group that
help others be sharing
what you have learned about debugging technique.

Two years ago when I was building my first board, an N8VEM SBC V2, I
never dreamed that the
time would come, and so quickly, that would find me helping others learn
the techniques of
hardware debugging.

We all have the same madness. We know in our hearts that the boards
should work, and we
don't want to give up when we might be so close. Very often it is just
one or two things not
quite right, and when you get near the end of the trouble, there is a
big thrill when those words
you live for pop out of the board.

After I built the SBC V2, I built other ECB boards. But my next SBC was
the Zeta, which is a lot of fun.

Beyond that I finally built an N8-2312, which was about three to four
times more complex. It all
really comes down to plumbing. The signals need to pass from one spot to
another, then another
and if you go where they start and trace them through, verifying at each
point where they look
good, eventually you verify that the signals seem to be moving well, and
about that time your
board suddenly starts working.

Warmly,

Douglas Goodall
Santa Maria,, CA




On 2/17/2013 11:44 PM, Ronald Bruinsma wrote:
> Hi Sergey,
>
> Thanks for your help!
>
> I will continue this afternoon I'am now on my work ;)
>
> I will post the outcome on the forum.
>
> Regards, Ronald
>
>
> 2013/2/18 Sergey <ski...@gmail.com>:
>> Good, now you can continue with troubleshooting :-)
>>
>> Can you please test A0 and /MREQ for pulses?
>>
>> Thanks,
>> Sergey
>>
>> On Feb 17, 12:04 pm, rbruinsma <rbma...@gmail.com> wrote:
>>> I did removed all IC's and re-tipped the most solder point again. After
>>> that I have double checked all Vcc and Ground pins from all sockets and I
>>> get all 5V readings.
>>>
>>> After putting back the IC's I now do get a 5V reading between pin 11&29 on
>>> the CPU. Also I get a High on pin 24/25 &26 on the CPU. But still no
>>> working SBC.
>>>
>>> Op zondag 17 februari 2013 19:49:48 UTC+1 schreef Sergey het volgende:
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>>>   When I measure the voltage between pin11 and 29 on the CPU I get 1.4V
>>>> but
>>>>> when I measure between pin 11 and ground on the power supply pin I get
>>>> 5.0V
>>>>> Any Idea where to look? What could cause the 1.4V reading on the CPU?
>>>> This is not good. If you have your ICs socketed, I'd take them out
>>>> first, and check continuity on power lines - between power connector
>>>> to ICs. Note that power pin numbers differ between ICs. For most 74*
>>>> logic, ground is the last pin in the first row (7 for 14 pin package,
>>>> 8 for 16 pin, 10 for 20 pin) and Vcc is the last pin (14 for 14 pin,
>>>> etc). Same for flash/EPROM/SRAM - pin 16 is ground, pin 32 is Vcc.
>>>> Consult ICs datasheets to find power pins for other ICs. (I think
>>>> schematic omits power inputs in most cases)
>>>> Thanks,
>>>> Sergey
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>
>
> --
> Met vriendelijke groet / Best Regards,
>
> Ronald Bruinsma
>
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