[hpsdr] Resoldering the ADC on Mercury

[Todd Mondragon]

Cool, I'll take a look through the binoscopes and see if it looks good.
Like I said it hasn't been running yet but I was wondering if it might be a
problem with that many open holes. If it's not an issue I'll leave it as is
and take a reading when it's at operating temp to see if it's getting up
around 100c or so.
If it's less than 70c as others in the past have reported I'll let it slide.

Just wanted to know if some preemptive action might be necessary and what
should be done if it was based on the number of visibly open heat pipes.

73!

Todd M0GLO

2009/4/8 Graham / KE9H <KE9H at austin.rr.com>

> Todd:
>
> Are you really sure you have a problem?
>
> That is a very expensive board, and you don't want to hurt it,
> particularly if it is working OK.  Just because the IC and the back
> side heat pad are hot to the touch, and you can't hold your fingers
> on them more than two seconds does not mean that you have
> a problem.  It just means that they are above 128 degrees F.
>
> I would not do anything to the board without temperature
> data.
>
> Just because the through-hole is open at the top (back-side heat pad)
> of the PC board, does not mean that you have a soldering
> problem.  Reflow soldering is NOT intended to fill the through
> holes.  In fact if all of the through holes were filled, it is indicative
> of a soldering problem (unless the board went through a special
> process intended to fill the holes.)
>
> If you have an inspection microscope, look at the bottom
> of each through hole (down by the heat pad at the IC, and yes
> they are small holes.)  If the hole is not filled, but there is a
> meniscus  at the bottom of each hole, then the reflow soldering
> process did its job, and you do not have a soldering problem.
>
> If you want to fill the through holes to increase heat flow to
> the back side heat pad, then you will need a temperature controlled
> soldering iron.  I would personally recommend that you not
> go above about 660 deg F., use a good flux, good tin-lead
> eutectic solder, and limit your working time to 30 seconds or so
> to not start cooking the board.
>
> But my real advise is to not do anything unless you are sure
> you have a problem.  Those ICs are designed to live longer than
> you will, running at temperatures that you consider hot to the touch.
>
> --- Graham / KE9H
>
> ==
>
>
>
> Todd Mondragon wrote:
>
>> Hi all,
>>  I seem to have one of the Mercury boards with soldering issues on the ADC
>> heatpad.
>> 11 of the 34 holes show no solder flow at all (most are around the edges
>> with 2 in the middle of the pad). I have not hooked it up yet to check the
>> temperature but I suspect this may be enough of a sign that I'd want to
>> reflow the ADC heat pad anyway.
>>
>> What would be the best method to make sure I've got a good contact between
>> the board and chip and that I have have all the heat pipes soldered through,
>> those holes are pretty small! Unfortunately all I have at my disposal for
>> this work is a pencil iron.
>>
>> Or is the experience of the group such that there shouldn't be a problem
>> and that I should not worry about it?
>>
>> BTW - This is no reflection on the folks at TAPR or anyone else, I
>> completely understand this is an experimenters kit and have no problem
>> fixing any issues I may encounter on my own. The folks at TAPR and the
>> people who designed and made this equipment possible are tops in my book.
>>
>> 73!
>>
>> Todd M0GLO
>>
>>
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