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Heat probe for localizing defective devices?

J

JW

Jan 1, 1970
0
Hello,

When doing repair work, I often run into components that fail to work
properly when they heat up. Usually, I use freeze spray to try to localize
the problem, but it's getting to the point where components are becoming
so close together that the freeze spray affects too many devices on the
PCB. Does anyone know of a off-the-shelf device or piece of test equipment
that would allow one to heat up individual components on a circuit board?
something that would have a tip maybe 3 to 5mm. square or so, and have a
controlled output from 40-100c.

Thanks for any suggestions.
 
N

N_Cook

Jan 1, 1970
0
JW said:
Hello,

When doing repair work, I often run into components that fail to work
properly when they heat up. Usually, I use freeze spray to try to localize
the problem, but it's getting to the point where components are becoming
so close together that the freeze spray affects too many devices on the
PCB. Does anyone know of a off-the-shelf device or piece of test equipment
that would allow one to heat up individual components on a circuit board?
something that would have a tip maybe 3 to 5mm. square or so, and have a
controlled output from 40-100c.

Thanks for any suggestions.


An old soldering iron with 1N4006 and selection of droppers in power line
and a calibration chart ?
Also a small accurate localised thermometer probe can be just a 1N4148 and
diode function of DVM, again calibrated with pan of heated water or
whatever.
 
J

JW

Jan 1, 1970
0
An old soldering iron with 1N4006 and selection of droppers in power line
and a calibration chart ?
Also a small accurate localised thermometer probe can be just a 1N4148 and
diode function of DVM, again calibrated with pan of heated water or
whatever.

Thanks, but I'm looking for something a little more professional that's
easy to use and reproducible temperature-wise. Something like you describe
would be temperature dependant on thermal load - a larger device would
cause the tip to become cooler and a smaller device hotter. I'd like to be
able to apply a precise temperature to devices from a SOT-23 to a TO-220.
I spent an hour or two doing some additional searching, and found this:
http://www.micro-technical.com/

I've got a request in for pricing and availability, Hopefully it won't be
much more than $500 or so...
 
J

JW

Jan 1, 1970
0
JW wrote:
[...]
Thanks, but I'm looking for something a little more professional that's
easy to use and reproducible temperature-wise. Something like you describe
would be temperature dependant on thermal load - a larger device would
cause the tip to become cooler and a smaller device hotter. I'd like to be
able to apply a precise temperature to devices from a SOT-23 to a TO-220.
I spent an hour or two doing some additional searching, and found this:
http://www.micro-technical.com/

I've got a request in for pricing and availability, Hopefully it won't be
much more than $500 or so...

What about somethng like this
http://cpc.farnell.com/jsp/level5/module.jsp?moduleId=cpc/275626.xml

That only measures temperature. I've already got plenty of instruments
that do that. I'm trying do deliver controlled heat to a device, not just
measure it.

Thanks though.
 
Y

Yukio YANO

Jan 1, 1970
0
JW said:
Hello,

When doing repair work, I often run into components that fail to work
properly when they heat up. Usually, I use freeze spray to try to localize
the problem, but it's getting to the point where components are becoming
so close together that the freeze spray affects too many devices on the
PCB. Does anyone know of a off-the-shelf device or piece of test equipment
that would allow one to heat up individual components on a circuit board?
something that would have a tip maybe 3 to 5mm. square or so, and have a
controlled output from 40-100c.

Thanks for any suggestions.
NIGHT VISION GOGGLES ???

Supposed to see the heat difference between bkgrnd and a human body !
Go talk to the local fire department ?

Yukio YANO
 
A

Archon

Jan 1, 1970
0
JW said:
Thanks, but I'm looking for something a little more professional that's
easy to use and reproducible temperature-wise. Something like you describe
would be temperature dependant on thermal load - a larger device would
cause the tip to become cooler and a smaller device hotter. I'd like to be
able to apply a precise temperature to devices from a SOT-23 to a TO-220.
I spent an hour or two doing some additional searching, and found this:
http://www.micro-technical.com/

I've got a request in for pricing and availability, Hopefully it won't be
much more than $500 or so...

Theres one on Ebay # 380069209309 $557

A similar function, obviously less controlled, but somewhat cheaper
would be to use a SMD hot air rework station with a fine outlet, eg.
http://store.sra-solder.com/product.php?xProd=6264&xSec=26

There is a tip available 2.5mm
http://store.sra-solder.com/product.php?xProd=6269&xSec=53

You may be able to extend the small outlet for a cooler airflow and
recalibrate the readout temp to correspond to the blow temp.

I have a similar unit which I have, as a last resort, used to fault find
temp sensitive faults, but I didn't need to know the air temp precisely
to generate the fault condition.

JC
 
B

Bob Larter

Jan 1, 1970
0
JW said:
Hello,

When doing repair work, I often run into components that fail to work
properly when they heat up. Usually, I use freeze spray to try to localize
the problem, but it's getting to the point where components are becoming
so close together that the freeze spray affects too many devices on the
PCB. Does anyone know of a off-the-shelf device or piece of test equipment
that would allow one to heat up individual components on a circuit board?
something that would have a tip maybe 3 to 5mm. square or so, and have a
controlled output from 40-100c.

Just use your soldering iron - carefully!
 
J

JB

Jan 1, 1970
0
JW said:
Hello,

When doing repair work, I often run into components that fail to work
properly when they heat up. Usually, I use freeze spray to try to localize
the problem, but it's getting to the point where components are becoming
so close together that the freeze spray affects too many devices on the
PCB. Does anyone know of a off-the-shelf device or piece of test equipment
that would allow one to heat up individual components on a circuit board?
something that would have a tip maybe 3 to 5mm. square or so, and have a
controlled output from 40-100c.

Thanks for any suggestions.

When it fails, troubleshoot and replace the bad part? Search for 2 hours on
the Internet? Did you land a big contract to evaluate the thermal design of
the UUT?
 
J

Jim Yanik

Jan 1, 1970
0
Old trick with freeze spray, hold can upside down and press just hard
enough to develop one drop on the end of the pipette. Takes a little
practice but you can control it well.

I use a soldering iron to heat components like capacitors. Usually
just a touch in the middle of a PC mount style or on the solder side.
These are both techniques that need a little practice but can be
valuable once you get the hang of it.

spray coolant onto Q-tip swab,press swab against suspect component.
repeat as needed.
 
G

GregS

Jan 1, 1970
0
spray coolant onto Q-tip swab,press swab against suspect component.
repeat as needed.

That would work. I was thinking of a dry ice stick. How about
a thermal electric stick ? You could also make a TE air stick.
Works in either heat or cold mode.

greg
 
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