Grant wrote:

On Fri, 28 May 2010 07:49:01 -0700, Winston wrote:

On 5/28/2010 1:03 AM, N_Cook wrote:
wrote in message
...
wrote in message
...
On 5/27/2010 7:42 AM, N_Cook wrote:

(...)

I like the solder paste indicator.

It works 'better than nothing'.
Of course the virgin solder melts at a much lower temperature
than does the used solder.

--Winston


Another reason to investigate these , but 1/2 deg C resolution fine for
that
purpose. For general fault hotspot monitoring 0.1 deg C resolution ones
would be more useful but too expensive.

I dunno. Plus / minus 10 C is all that is necessary.
Your real indication is when you can lift the BGA off the board
without undue drama.

I tap the board to encourage components to 'unstick' from the molten
solder.

Another gizmo I must get around to
trying. Using the pyrometer of a PIR unit , setting in an insulated tube
shroud for pointing and then analogue fashion monitor the output in a
relative way, absolute temp not required for that purpose.

I understand that PIRs are A.C. devices, so one would have to be adept
at 'blinking' the shroud at the target while capturing the resulting
pulse from the PIR. As you say below, there is a much better solution.

Yeah, PIR detector is hopeless at absolute temperature. What it does
instead is rely on the warm body moving in and out of the lensed zones
to create an AC IR signal. That's why they have that fresnel lens thing
on them to define the IR zones.

In this situation would thore remote IR thermometers pick up the temp of the
board or the much higher temp of the hot air above it , but in line of
"sight" of the sensor?

That is a good experiment to do.

I *guess* that the infrared emissivity of nitrogen *at that temperature*
is low enough that the infrared from the PCB would swamp it out.
I do not know for sure.

Product Idea! An infrared sensor mounted to your headband magnifier.

Lensed LCD chart presented as a heads-up display in your magnifier
continuously scrolls to show temperature at the center of your crosshairs.

Hmm, seen the price of a point-at-target IR thermometer? Add a couple
more times that for the headsup display? Not cheap


$10 on sale at Harbor Freight.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.