Extending the life of a Tek 2465?

[als]

John beat me to it.
Copper shim stock and copper water pipe is your friend
for odd heat sink configurations. Especially if you need
to make some convoluted shape to conform to the space.
Clean it well.
<als>


In article <nIOcUYG5HL1$Ew4x@jmwa.demon.co.uk>, jmw@jmwa.demon.contraspam.yuk says...

Incidentally, I make heat sinks for my own stuff and
repairs/improvements out of bits of scrap copper water pipe.
--
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[Airy R. Bean]

Copper water pipe is also your friend if you
need a specially-shaped bit for your soldering-iron.


"als" <als73@hotmail.com> wrote in message
news:3fe035bb$0$187$a726171b@news.hal-pc.org...

John beat me to it.
Copper shim stock and copper water pipe is your friend
for odd heat sink configurations. Especially if you need
to make some convoluted shape to conform to the space.
Clean it well.

 

[DaveC]

On Wed, 17 Dec 2003 4:16:06 -0800, Airy R. Bean wrote
(in message <brphm4$60b78$1@ID-217727.news.uni-berlin.de&gt:

Copper water pipe is also your friend if you
need a specially-shaped bit for your soldering-iron.

This sounds interesting... Photos?
--
DaveC
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[DaveC]

On Wed, 17 Dec 2003 2:53:47 -0800, als wrote
(in message <3fe035bb$0$187$a726171b@news.hal-pc.org&gt:

Copper shim stock and copper water pipe is your friend
for odd heat sink configurations. Especially if you need
to make some convoluted shape to conform to the space.
Clean it well.

I need something 2.5 mm (a little less than 0.1 inch) thick. I know I can
layer more than 1 piece, but would like to reduce the thermal interfaces to
just 2 (tab to shim; shim to heat sink).

Do water pipe or other off-the-shelf copper come in such thick sections? (the
US penny -- early production dates -- comes to mind...)

Thanks,
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[John Woodgate]

I read in sci.electronics.design that DaveC <me@privacy.net> wrote (in
<0001HW.BC0D95180091E6B4F0080600@news.individual.net&gt about 'Extending
the life of a Tek 2465?', on Tue, 23 Dec 2003:

I need something 2.5 mm (a little less than 0.1 inch) thick. I know I can
layer more than 1 piece, but would like to reduce the thermal interfaces to
just 2 (tab to shim; shim to heat sink).

Layers would lose you a lot of thermal conductivity. For 2.5 mm sheet or
bar, I'd try a non-ferrous metal scrap merchant. On a good day, they
sell it by the pound; on a bad day by the carat.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[Spehro Pefhany]

On Tue, 23 Dec 2003 16:08:04 +0000, the renowned John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that DaveC <me@privacy.net> wrote (in
0001HW.BC0D95180091E6B4F0080600@news.individual.net&gt about 'Extending
the life of a Tek 2465?', on Tue, 23 Dec 2003:

I need something 2.5 mm (a little less than 0.1 inch) thick. I know I can
layer more than 1 piece, but would like to reduce the thermal interfaces to
just 2 (tab to shim; shim to heat sink).

Layers would lose you a lot of thermal conductivity. For 2.5 mm sheet or
bar, I'd try a non-ferrous metal scrap merchant. On a good day, they
sell it by the pound; on a bad day by the carat.

3/32" (2.4mm) copper flats are a standard size (in 1/2" , 5/8", 3/4",
1", 2" width, by whatever length). There are retail shops that sell
this stuff, at a real premium in price, but you can buy just a small
amount if that's what you need.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[DaveC]

On Tue, 23 Dec 2003 8:08:04 -0800, John Woodgate wrote:

I read in sci.electronics.design that DaveC <me@privacy.net> wrote:

I need something 2.5 mm (a little less than 0.1 inch) thick. I know I can
layer more than 1 piece, but would like to reduce the thermal interfaces
to just 2 (tab to shim; shim to heat sink).

Layers would lose you a lot of thermal conductivity. For 2.5 mm sheet or
bar, I'd try a non-ferrous metal scrap merchant. On a good day, they
sell it by the pound; on a bad day by the carat.

Would soldering the 2.5 mm copper shim to a copper heat sink increase the
thermal conductivity? Or is thermal compound between the copper shim and an
aluminum sink best? Or use an aluminum shim and an aluminum sink?

Suggestions welcome.

Thanks,
--
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[DaveC]

On Tue, 23 Dec 2003 8:29:51 -0800, Spehro Pefhany wrote:

3/32" (2.4mm) copper flats are a standard size (in 1/2" , 5/8", 3/4",
1", 2" width, by whatever length). There are retail shops that sell
this stuff, at a real premium in price, but you can buy just a small
amount if that's what you need.

Is this otherwise known as "bar stock"?

Thanks,
--
DaveC
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[Spehro Pefhany]

On Tue, 23 Dec 2003 8:32:01 -0800, the renowned DaveC <me@privacy.net>
wrote:

On Tue, 23 Dec 2003 8:29:51 -0800, Spehro Pefhany wrote:

3/32" (2.4mm) copper flats are a standard size (in 1/2" , 5/8", 3/4",
1", 2" width, by whatever length). There are retail shops that sell
this stuff, at a real premium in price, but you can buy just a small
amount if that's what you need.

Is this otherwise known as "bar stock"?

Yes, one type of copper bar stock.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Richard Crowley]

Airy R. Bean wrote

Copper water pipe is also your friend if you
need a specially-shaped bit for your soldering-iron.

#10 or #12 solid wire (used for house mains wiring)
is good for making "specialty tips" for your soldering
gun. Very handy for scooping out custom-size/shape
cavities in foam for storing small items (microphones,
etc.)

 

[N. Thornton]

Airy R. Bean wrote
Copper water pipe is also your friend if you
need a specially-shaped bit for your soldering-iron.

Call me hignorant but how are you going to make a slobbering iron bit
out of water pipe?

Regards, NT

 

[mike]

DaveC wrote:

On Tue, 23 Dec 2003 8:08:04 -0800, John Woodgate wrote:


I read in sci.electronics.design that DaveC <me@privacy.net> wrote:


I need something 2.5 mm (a little less than 0.1 inch) thick. I know I can
layer more than 1 piece, but would like to reduce the thermal interfaces
to just 2 (tab to shim; shim to heat sink).


Layers would lose you a lot of thermal conductivity. For 2.5 mm sheet or
bar, I'd try a non-ferrous metal scrap merchant. On a good day, they
sell it by the pound; on a bad day by the carat.


Would soldering the 2.5 mm copper shim to a copper heat sink increase the
thermal conductivity? Or is thermal compound between the copper shim and an
aluminum sink best? Or use an aluminum shim and an aluminum sink?

Suggestions welcome.

Thanks,

I've been following this thread with interest.
Had to check the header to make sure this wasn't
rec.plumbing.
I don't know whether to laugh or be sad.

What's the first thing one should do when designing a heat sink
for an unknown component?
MEASURE THE TEMPERATURE OF THE DEVICE TO BE HEAT SINKED/SUNK!
If anybody published that number for the chip in question, I missed it;
Please repost. It would also be nice to have a second number with a
known heat sink so we could estimate power/heat flow.

Without numbers, we have no idea whether this is a fix
for something that ain't broke. Yes, cooler is almost always better,
but there is a thing called diminishing returns. Just opening the
box and poking your screwdriver in there entails risk.

Heat sinking is a network (often a series string) of (thermal) resistances.
Do the math. It should be obvious from the materials and the
temperature difference (see, this is where you need to know the
temperature of the device) where the critical resistances are.

There are reasons why virtually every heat sink on the planet is made
from aluminum. Makes absolutely no sense to worry about the differences
between aluminum and copper when you don't have any idea how much
heat you need to remove...or when you're gonna put in a bunch of
extra (bad thermal) interfaces. Typically, the first tiny bit of
heat sinking makes a big difference. It's all downhill, asymptotically,
from there.

Just to throw gas on the confusion, anybody looked at putting in a
small length of tubing to direct some air flow on the chip? But then
we'd have to measure the temperature to see if it worked...and that
ain't gonna happen. ;-(

mike
Did I mention that someone should measure the *#$%^& temperature????
--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
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Honda CB-125S $800 in PDX
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[John Woodgate]

I read in sci.electronics.design that N. Thornton <bigcat@meeow.co.uk>
wrote (in <a7076635.0312231412.43f2c535@posting.google.com&gt about
'Copper (was: Extending the life of a Tek 2465?)', on Tue, 23 Dec 2003:

Airy R. Bean wrote
Copper water pipe is also your friend if you
need a specially-shaped bit for your soldering-iron.

Call me hignorant but how are you going to make a slobbering iron bit
out of water pipe?

Cut a short piece longitudinally, flatten it and roll it up.

--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[DaveC]

On Tue, 23 Dec 2003 14:21:38 -0800, mike wrote
(in message <3FE8BFF2.9070001@juno.com&gt:

What's the first thing one should do when designing a heat sink
for an unknown component?
MEASURE THE TEMPERATURE OF THE DEVICE TO BE HEAT SINKED/SUNK!
If anybody published that number for the chip in question, I missed it;
Please repost. It would also be nice to have a second number with a
known heat sink so we could estimate power/heat flow.

I (OP) am using something I call intuitive logic. Some like to call it
SWAG'ing.

This chip dies in this model scope. Frequently. It is considered a high
failure component. There is *no* replacement for this component available
from new sources, only scavenged ones. And expensive. All failures not caused
by reckless use (ie, overvoltage, etc.) are thermal failures, whether short
term or long term, IMO. Heat sinking -- *any* heat sinking -- is going to
reduce the risk of failure.

So even a non-scientific attempt, as long as the methods employed (proper
materials, reasonable craftsmanship) are not sloppy, is going to improve the
probability that my investment in this scope will be protected. At least more
so than if I left it w/o a sink.

Yes, measuring temperatures and calculating the size of the sink would give
me the exact protection I need, but if I shoot for overkill and am reasonably
confident that I've achieved this, there's no need for engineering a
solution.

A bit unscientific, maybe. But so what? SWAG is good enough for me, in this
application.

Not every solution *needs* to be scientifically calculated.
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[mike]

DaveC wrote:

On Tue, 23 Dec 2003 14:21:38 -0800, mike wrote
(in message <3FE8BFF2.9070001@juno.com&gt:


What's the first thing one should do when designing a heat sink
for an unknown component?
MEASURE THE TEMPERATURE OF THE DEVICE TO BE HEAT SINKED/SUNK!
If anybody published that number for the chip in question, I missed it;
Please repost. It would also be nice to have a second number with a
known heat sink so we could estimate power/heat flow.


I (OP) am using something I call intuitive logic. Some like to call it
SWAG'ing.

This chip dies in this model scope. Frequently. It is considered a high
failure component. There is *no* replacement for this component available
from new sources, only scavenged ones. And expensive. All failures not caused
by reckless use (ie, overvoltage, etc.) are thermal failures, whether short
term or long term, IMO. Heat sinking -- *any* heat sinking -- is going to
reduce the risk of failure.

This is likely true for the part of the failure equation that involves
heat at the point your're heat sinking. That ain't the only possible
failure mode.

So even a non-scientific attempt, as long as the methods employed (proper
materials, reasonable craftsmanship) are not sloppy, is going to improve the
probability that my investment in this scope will be protected. At least more
so than if I left it w/o a sink.

I haven't heard ANY basis for this assumption.
Taking it apart involves risk.
Torquing on the screws and the resultant change in stress on the pins
involves risk. What if I told you that the failure rate was due to
moisture entering the package because the pins are thermally stressed
cause the tab is bolted down?

Yes, measuring temperatures and calculating the size of the sink would give
me the exact protection I need, but if I shoot for overkill and am reasonably
confident that I've achieved this, there's no need for engineering a
solution.

A bit unscientific, maybe. But so what? SWAG is good enough for me, in this
application.

Not every solution *needs* to be scientifically calculated.

Yep, but every solution should have a *problem*.
How do you know you're shooting for overkill when you don't
even know which direction you're shooting? Confidence based on no
data??


So, you're saying you don't have any idea how hot it is and you don't
care. That's sad for me 'cause now I have to take mine apart and
measure the damned thing to determine whether I should have taken it apart.

It's been interesting to watch this thread twist and turn based on
absolutely ZERO, none, not any data. I mean, you've had the thing apart
multiple times. Is it so hard to stick a thermocouple on it for
a few seconds???

I'll measure mine, but I'll keep the data a secret....

Thanks, anyway,
mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[DaveC]

On Fri, 26 Dec 2003 4:16:00 -0800, mike wrote
(in message <3FEC2680.4060509@juno.com&gt:

So, you're saying you don't have any idea how hot it is and you don't
care. That's sad for me 'cause now I have to take mine apart and
measure the damned thing to determine whether I should have taken it apart.

It's been interesting to watch this thread twist and turn based on
absolutely ZERO, none, not any data. I mean, you've had the thing apart
multiple times. Is it so hard to stick a thermocouple on it for
a few seconds???

Don't own a thermocouple. Don't know anyone who does. Is it worth it to rent
one? Probably not. My judgement call. Maybe a bad one, maybe not.

As to the possibility that failure is due to other modes, well there's
nothing I can do to ameliorate those, but reducing the heat of the device
could help reduce the possibility of failure in these modes. Heat could be a
contributing factor.

*Any* heat sinking will help this situation.

I'll measure mine, but I'll keep the data a secret....

I'm sorry to hear that. Not that I can't have your data; I don't feel the
need to collect it or use any. SWAG is fine for me. I am sorry that you don't
feel that you want to contribute to others that might be looking at this
thread that might find your data useful , this being a public "help each
other as best you can" forum.

Good luck,
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