Sign in with
Sign up | Sign in
Your question

Testing large number of processors

Last response: in CPUs
Share
Anonymous
a b à CPUs
May 20, 2005 1:28:17 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

I have a large inflow of processors that I'm acquiring
from liquidators. A significant percentage of these
are defective, and I'm reselling them to people who
expect all working processors, so they must be
tested.

I need some advice on how to go about this:

1. How do I provide heat dissipation during testing?
To be safe, do I need to use apply thermal paste or a
thermal pad to every one? That'll get expensive.
Do I need to clamp down the heatsink on every one?
That'll get very tedious. Is there any safe shortcut?

2. If I put an incompatible processor in a motherboard,
can I damage the chip and/or the motherboard?

3. How extensive a test do I need to perform? If a
processor posts or boots, how likely is it that it will have
some subtle defect that will take more extensive testing
to find?

Thanks
Anonymous
a b à CPUs
May 20, 2005 3:40:37 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

In article <pan.2005.05.20.15.28.17.201275@nospam.me.noway>,
A Jones <ajones@nospam.me.noway> wrote:
>I have a large inflow of processors that I'm acquiring
>from liquidators. A significant percentage of these
>are defective, and I'm reselling them to people who
>expect all working processors, so they must be
>tested.
>
>I need some advice on how to go about this:
>
>1. How do I provide heat dissipation during testing?
>To be safe, do I need to use apply thermal paste or a
>thermal pad to every one? That'll get expensive.
>Do I need to clamp down the heatsink on every one?
>That'll get very tedious. Is there any safe shortcut?
>
>2. If I put an incompatible processor in a motherboard,
>can I damage the chip and/or the motherboard?
>
>3. How extensive a test do I need to perform? If a
>processor posts or boots, how likely is it that it will have
>some subtle defect that will take more extensive testing
>to find?
>
>Thanks
>


Since you'll be selling these CPUs as used with return privilages I
suggest you'll net the most cash in you just give people a money back
guarantee.

As you suspect, testing to the point you can give a better guarantee
would be very expensive and involve testing to timing and voltage
margins.



--
a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
a b à CPUs
May 20, 2005 3:40:38 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 11:40:37 -0400, Al Dykes wrote:

> In article <pan.2005.05.20.15.28.17.201275@nospam.me.noway>,
> A Jones <ajones@nospam.me.noway> wrote:
>>I have a large inflow of processors that I'm acquiring
>>from liquidators. A significant percentage of these
>>are defective, and I'm reselling them to people who
>>expect all working processors, so they must be
>>tested.
>>
>>I need some advice on how to go about this:
>>
>>1. How do I provide heat dissipation during testing?
>>To be safe, do I need to use apply thermal paste or a
>>thermal pad to every one? That'll get expensive.
>>Do I need to clamp down the heatsink on every one?
>>That'll get very tedious. Is there any safe shortcut?
>>
>>2. If I put an incompatible processor in a motherboard,
>>can I damage the chip and/or the motherboard?
>>
>>3. How extensive a test do I need to perform? If a
>>processor posts or boots, how likely is it that it will have
>>some subtle defect that will take more extensive testing
>>to find?
>>
>>Thanks
>>
>
>
> Since you'll be selling these CPUs as used with return privilages I
> suggest you'll net the most cash in you just give people a money back
> guarantee.
>
> As you suspect, testing to the point you can give a better guarantee
> would be very expensive and involve testing to timing and voltage
> margins.

That'll work up to a point, but many liquidation lots have 50% or
more dead processors. If a customer has to return half the processors
I send them, they won't be a customer very long.

A reasonable strategy might be to resell all the processors that post.
I'm assuming that if a processor posts, chances are pretty good that
it is fully functional. Do people here agree?
Related resources
Anonymous
a b à CPUs
May 20, 2005 9:43:51 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Bitstring <pan.2005.05.20.16.25.52.369222@nospam.me.noway>, from the
wonderful person A Jones <ajones@nospam.me.noway> said
<snip>
>A reasonable strategy might be to resell all the processors that post.
>I'm assuming that if a processor posts, chances are pretty good that
>it is fully functional. Do people here agree?

Yes; That's probably more testing (in terms of cycles/time, if not
parametrics) than Intel or AMD gave it originally. Testing processors
for all possibly failure modes is ludicrously expensive, Joe Consumer
would rather have it $50 cheaper with a 1% false-pass and a money back
warranty.

Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.

--
GSV Three Minds in a Can
Contact recommends the use of Firefox; SC recommends it at gunpoint.
Anonymous
a b à CPUs
May 20, 2005 9:43:52 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 17:43:51 +0100, GSV Three Minds in a Can wrote:

> Bitstring <pan.2005.05.20.16.25.52.369222@nospam.me.noway>, from the
> wonderful person A Jones <ajones@nospam.me.noway> said
> <snip>
>>A reasonable strategy might be to resell all the processors that post.
>>I'm assuming that if a processor posts, chances are pretty good that
>>it is fully functional. Do people here agree?
>
> Yes; That's probably more testing (in terms of cycles/time, if not
> parametrics) than Intel or AMD gave it originally. Testing processors
> for all possibly failure modes is ludicrously expensive, Joe Consumer
> would rather have it $50 cheaper with a 1% false-pass and a money back
> warranty.
>
> Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.


OK, that makes sense. I still have to work out heat dissipation during
testing. I've heard that a P4 can be damaged in a matter of seconds
if it doesn't have proper heat dissipation. Do I need to put thermal
paste clamp down a heatsink on every one of these?
Anonymous
a b à CPUs
May 21, 2005 1:10:11 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Bitstring <pan.2005.05.20.17.01.13.439094@nospam.me.noway>, from the
wonderful person A Jones <ajones@nospam.me.noway> said
>On Fri, 20 May 2005 17:43:51 +0100, GSV Three Minds in a Can wrote:
>
>> Bitstring <pan.2005.05.20.16.25.52.369222@nospam.me.noway>, from the
>> wonderful person A Jones <ajones@nospam.me.noway> said
>> <snip>
>>>A reasonable strategy might be to resell all the processors that post.
>>>I'm assuming that if a processor posts, chances are pretty good that
>>>it is fully functional. Do people here agree?
>>
>> Yes; That's probably more testing (in terms of cycles/time, if not
>> parametrics) than Intel or AMD gave it originally. Testing processors
>> for all possibly failure modes is ludicrously expensive, Joe Consumer
>> would rather have it $50 cheaper with a 1% false-pass and a money back
>> warranty.
>>
>> Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.
>
>
>OK, that makes sense. I still have to work out heat dissipation during
>testing. I've heard that a P4 can be damaged in a matter of seconds
>if it doesn't have proper heat dissipation. Do I need to put thermal
>paste clamp down a heatsink on every one of these?

For 'just POST' (and maybe boot into Windows) you could probably get
away with no paste but just a HS. I've done it with no fan before now.
8>.

The P4s, and modern Athlons, all thermally throttle (the Athlon probably
needs a motherboard which co-operates). They'll lock up before they
self-destruct (usually) anyway. The scare stories are about old Athlons
running with no HS at all .. not anything halfway modern with a lousy
one.

--
GSV Three Minds in a Can
Contact recommends the use of Firefox; SC recommends it at gunpoint.
Anonymous
a b à CPUs
May 21, 2005 1:10:12 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 21:10:11 +0100, GSV Three Minds in a Can wrote:

> Bitstring <pan.2005.05.20.17.01.13.439094@nospam.me.noway>, from the
> wonderful person A Jones <ajones@nospam.me.noway> said
>>On Fri, 20 May 2005 17:43:51 +0100, GSV Three Minds in a Can wrote:
>>
>>> Bitstring <pan.2005.05.20.16.25.52.369222@nospam.me.noway>, from the
>>> wonderful person A Jones <ajones@nospam.me.noway> said
>>> <snip>
>>>>A reasonable strategy might be to resell all the processors that post.
>>>>I'm assuming that if a processor posts, chances are pretty good that
>>>>it is fully functional. Do people here agree?
>>>
>>> Yes; That's probably more testing (in terms of cycles/time, if not
>>> parametrics) than Intel or AMD gave it originally. Testing processors
>>> for all possibly failure modes is ludicrously expensive, Joe Consumer
>>> would rather have it $50 cheaper with a 1% false-pass and a money back
>>> warranty.
>>>
>>> Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.
>>
>>
>>OK, that makes sense. I still have to work out heat dissipation during
>>testing. I've heard that a P4 can be damaged in a matter of seconds
>>if it doesn't have proper heat dissipation. Do I need to put thermal
>>paste clamp down a heatsink on every one of these?
>
> For 'just POST' (and maybe boot into Windows) you could probably get
> away with no paste but just a HS. I've done it with no fan before now.
> 8>.
>
> The P4s, and modern Athlons, all thermally throttle (the Athlon probably
> needs a motherboard which co-operates). They'll lock up before they
> self-destruct (usually) anyway. The scare stories are about old Athlons
> running with no HS at all .. not anything halfway modern with a lousy
> one.

Ok, that's good to know. However, I find that the mechanism for
clamping and unclamping a heatsink on just about any Intel processor is
incredibly awkward. I'd almost rather put some thermal paste and rest the
heatsink on without clamping it -- if that works. It'd be more expensive
of course, but it'd be longer before I go nuts and the guys with the
straight jackets have to come.

What about Pentium IIIs? I'm getting fairly large numbers of them. The
slot 1's are okay because they usually have heatsinks attached. The
socket 370's usually come with no heatsink, so they're a problem. I
think they have no throttle mechanism. How fast can you damage one of
those?
Anonymous
a b à CPUs
May 21, 2005 1:44:51 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

GSV Three Minds in a Can <GSV@quik.clara.co.uk> wrote:
>>> Yes; That's probably more testing (in terms of cycles/time, if
>>> not parametrics) than Intel or AMD gave it originally. Testing
>>> processors for all possibly failure modes is ludicrously
>>> expensive, Joe Consumer would rather have it $50 cheaper with
>>> a 1% false-pass and a money back warranty.

Yes, but AFAIK both Intel and AMD spend considerable time
in testing (15+ minutes power-on). They use expensive gang
testers, starting with bed-o-nails (and cooling block?) before
the wafer is even sawed. After packaging, they still need
to speed test for binning, and I don't think that can be done
in under 5 minutes even with preheated blocks.

>>> Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.

Yes, but even for Dell a dead CPU costs more than the device's
purchase price. A subtly defective one costs _far_ more.
(Pentium FDIV bug).

> For 'just POST' (and maybe boot into Windows) you could
> probably get away with no paste but just a HS. I've done
> it with no fan before now.

No fan is much easier than no paste. The fan is only needed after
the block heats up, and that takes minutes. For a temporary TIM,
I'd suggest Vaseline (microcrystalline petroleum wax) if there
are exposed electrical points on the CPU topside, or K-Y Jelly
(thickened isotonic saline) if there are no conductivity issues.
The water in the latter is an _excellent_ thermal conductor.

CPUs do a BIST (Built-in self test) and the BIOS tests them
further, but you won't catch everything. It might not
catch a fried address line like A30.

There's _a lot_ to CPU testing, and Keith can comment
more knowledgably than me.

-- Robert
Anonymous
a b à CPUs
May 21, 2005 1:44:52 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

"Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
news:nTsje.2486$VB6.1517@newssvr12.news.prodigy.com...
> GSV Three Minds in a Can <GSV@quik.clara.co.uk> wrote:
>>>> Yes; That's probably more testing (in terms of cycles/time, if
>>>> not parametrics) than Intel or AMD gave it originally. Testing
>>>> processors for all possibly failure modes is ludicrously
>>>> expensive, Joe Consumer would rather have it $50 cheaper with
>>>> a 1% false-pass and a money back warranty.
>
> Yes, but AFAIK both Intel and AMD spend considerable time
> in testing (15+ minutes power-on). They use expensive gang
> testers, starting with bed-o-nails (and cooling block?) before
> the wafer is even sawed. After packaging, they still need
> to speed test for binning, and I don't think that can be done
> in under 5 minutes even with preheated blocks.

I would be willing to bet that there is some preliminary test in there to
get rid of the bad ones first, perhaps even with a reduced set of pins and a
cheap tester.
>
>>>> Joe Military/NASA/Etc. has a different viewpoint and deeper pockets.
>
> Yes, but even for Dell a dead CPU costs more than the device's
> purchase price. A subtly defective one costs _far_ more.
> (Pentium FDIV bug).
>
>> For 'just POST' (and maybe boot into Windows) you could
>> probably get away with no paste but just a HS. I've done
>> it with no fan before now.
>
> No fan is much easier than no paste. The fan is only needed after
> the block heats up, and that takes minutes. For a temporary TIM,
> I'd suggest Vaseline (microcrystalline petroleum wax) if there
> are exposed electrical points on the CPU topside, or K-Y Jelly
> (thickened isotonic saline) if there are no conductivity issues.
> The water in the latter is an _excellent_ thermal conductor.
Saline? You are going to put salt on there? How are you going to get it
off again?
>
> CPUs do a BIST (Built-in self test) and the BIOS tests them
> further, but you won't catch everything. It might not
> catch a fried address line like A30.
>
> There's _a lot_ to CPU testing, and Keith can comment
> more knowledgably than me.
>
> -- Robert
He just needs something to get the fallout down to a level low enough to not
piss off the customer that knows they are buying junk in the first place.
Are you old enough to remember PolyPacks?.

del cecchi
>
Anonymous
a b à CPUs
May 21, 2005 1:44:52 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 21:44:51 +0000, Robert Redelmeier wrote:

> CPUs do a BIST (Built-in self test) and the BIOS tests them
> further, but you won't catch everything. It might not
> catch a fried address line like A30.
>
> There's _a lot_ to CPU testing, and Keith can comment
> more knowledgably than me.

I'm really only looking for practical issues here. The
testing that Intel and AMD do before shipping the processor
is not necessarily relevant to my situation.

Likewise, if it's common for a single address line to burn out
in a chip that still posts, I need to consider it. If it's
something that might happen only occasionally, I can't
afford to test for it. I'm not doing research on these
chips, or certifying them for use in the space shuttle; I'm just
trying to make a living.
Anonymous
a b à CPUs
May 21, 2005 2:15:23 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

A Jones <ajones@nospam.me.noway> wrote:
> Ok, that's good to know. However, I find that the mechanism
> for clamping and unclamping a heatsink on just about any
> Intel processor is incredibly awkward. I'd almost rather
> put some thermal paste and rest the heatsink on without
> clamping it -- if that works.

It will, so long as the heatsink can fit dead flat
and isn't torqued around by the HSF or it's cable
or any of the attachment hardware.

> What about Pentium IIIs? I'm getting fairly large numbers

Die back like Athlons. Supposed to shutdown on overheat,
but if the heatsink is in edge contact, some parts may
see overheat damage just before shutdown.

-- Robert
Anonymous
a b à CPUs
May 21, 2005 2:40:14 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Del Cecchi <dcecchi.nospam@att.net> wrote:
> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
>> Yes, but AFAIK both Intel and AMD spend considerable time
>> in testing (15+ minutes power-on). They use expensive gang
>> testers, starting with bed-o-nails (and cooling block?) before
>> the wafer is even sawed. After packaging, they still need
>> to speed test for binning, and I don't think that can be done
>> in under 5 minutes even with preheated blocks.
>
> I would be willing to bet that there is some preliminary
> test in there to get rid of the bad ones first, perhaps
> even with a reduced set of pins and a cheap tester.

Yes, there probably is a quickie test after packaging to
test for open/shorted pins.

> He just needs something to get the fallout down to a level
> low enough to not piss off the customer that knows they
> are buying junk in the first place. Are you old enough to
> remember PolyPacks?.

I'm more than old enough (just shy of 30h), but don't remember
anything by that name.

-- Robert
Anonymous
a b à CPUs
May 21, 2005 2:40:15 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

"Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
news:iHtje.2266$5Z1.259@newssvr30.news.prodigy.com...
> Del Cecchi <dcecchi.nospam@att.net> wrote:
>> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
>>> Yes, but AFAIK both Intel and AMD spend considerable time
>>> in testing (15+ minutes power-on). They use expensive gang
>>> testers, starting with bed-o-nails (and cooling block?) before
>>> the wafer is even sawed. After packaging, they still need
>>> to speed test for binning, and I don't think that can be done
>>> in under 5 minutes even with preheated blocks.
>>
>> I would be willing to bet that there is some preliminary
>> test in there to get rid of the bad ones first, perhaps
>> even with a reduced set of pins and a cheap tester.
>
> Yes, there probably is a quickie test after packaging to
> test for open/shorted pins.
>
>> He just needs something to get the fallout down to a level
>> low enough to not piss off the customer that knows they
>> are buying junk in the first place. Are you old enough to
>> remember PolyPacks?.
>
> I'm more than old enough (just shy of 30h), but don't remember
> anything by that name.
>
> -- Robert

It was a company that sold bags of parts, sometimes "unmarked untested" for
low prices through ads in magazines like popular electronics. They have
apparently vanished into the mists some time ago.

del
>
>
>
Anonymous
a b à CPUs
May 21, 2005 2:46:11 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Del Cecchi <dcecchi.nospam@att.net> wrote:
> Saline? You are going to put salt on there?
> How are you going to get it off again?

With a tissue, of course. Isotonic is only 0.8%w.
The nanogram residue won't do anything to plastic
or silicon but could to copper.

-- Robert
Anonymous
a b à CPUs
May 21, 2005 2:46:12 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

"Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
news:TMtje.2275$5Z1.2231@newssvr30.news.prodigy.com...
> Del Cecchi <dcecchi.nospam@att.net> wrote:
>> Saline? You are going to put salt on there?
>> How are you going to get it off again?
>
> With a tissue, of course. Isotonic is only 0.8%w.
> The nanogram residue won't do anything to plastic
> or silicon but could to copper.
>
> -- Robert
>
Nanogram? I don't think so. And look up Sodium and threshold instability.
Goes back aways.

del
Anonymous
a b à CPUs
May 21, 2005 2:49:14 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

A Jones <ajones@nospam.me.noway> wrote:
> I'm really only looking for practical issues here.
> The testing that Intel and AMD do before shipping the
> processor is not necessarily relevant to my situation.

True. After all, these CPUs once _did_ pass.

> Likewise, if it's common for a single address line to burn
> out in a chip that still posts, I need to consider it.

Check the pinout. I consider any of the outside pins
likely candidates for ESD.

-- Robert
Anonymous
a b à CPUs
May 21, 2005 5:44:40 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 21:44:51 +0000, Robert Redelmeier wrote:

> No fan is much easier than no paste. The fan is only needed after
> the block heats up, and that takes minutes. For a temporary TIM,
> I'd suggest Vaseline (microcrystalline petroleum wax) if there
> are exposed electrical points on the CPU topside, or K-Y Jelly
> (thickened isotonic saline) if there are no conductivity issues.
> The water in the latter is an _excellent_ thermal conductor.

So let's say I go with Vaseline. Then there's no controversy about
whether the saline is a problem. Can I use Vaseline as a cheap
substitute for thermal paste that's adequate for a post or
even a boot to Windows?

If so, this is starting to sound like an attractive shortcut:
1. I coat the processor with Vaseline.
2. I rest a clean heatsink carefully on top of the processor
so it rests flat, but I don't clamp it down.
3. I do a post or even a boot to Windows.
4. If it boots, I sell it. If the buyer has a problem, I refund
or replace.

Does anyone have a practical objection to this approach?
May 21, 2005 6:28:28 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 22:01:04 -0500, Del Cecchi wrote:

>
> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
> news:iHtje.2266$5Z1.259@newssvr30.news.prodigy.com...
>> Del Cecchi <dcecchi.nospam@att.net> wrote:
>>> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
>>>> Yes, but AFAIK both Intel and AMD spend considerable time
>>>> in testing (15+ minutes power-on). They use expensive gang
>>>> testers, starting with bed-o-nails (and cooling block?) before
>>>> the wafer is even sawed. After packaging, they still need
>>>> to speed test for binning, and I don't think that can be done
>>>> in under 5 minutes even with preheated blocks.
>>>
>>> I would be willing to bet that there is some preliminary
>>> test in there to get rid of the bad ones first, perhaps
>>> even with a reduced set of pins and a cheap tester.
>>
>> Yes, there probably is a quickie test after packaging to
>> test for open/shorted pins.
>>
>>> He just needs something to get the fallout down to a level
>>> low enough to not piss off the customer that knows they
>>> are buying junk in the first place. Are you old enough to
>>> remember PolyPacks?.
>>
>> I'm more than old enough (just shy of 30h), but don't remember
>> anything by that name.
>>
>> -- Robert
>
> It was a company that sold bags of parts, sometimes "unmarked untested" for
> low prices through ads in magazines like popular electronics. They have
> apparently vanished into the mists some time ago.

Yep, "unmarked untested", but we know it has (or once had) 16 pins. They
were famous for selling "Digital IC - 16 pins - $.50". I did see some with
curious 7-digit part numbers in the form 'NNANNNN' (like 39F1234). ;-)

Their parts usually failed the floor-sweepings test. In reality they were
best used as thumb tacks.

--
Keith
May 21, 2005 6:39:52 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Fri, 20 May 2005 22:49:14 +0000, Robert Redelmeier wrote:

> A Jones <ajones@nospam.me.noway> wrote:
>> I'm really only looking for practical issues here.
>> The testing that Intel and AMD do before shipping the
>> processor is not necessarily relevant to my situation.
>
> True. After all, these CPUs once _did_ pass.

Assuming that these aren't floor-sweepings, sold out the back door, that's
a good point.

I think his only problem is cooling. With Socket-7 processors
we'd just sit a heatsink (no goop) on 'em and let gravity do the work.
This strategy isn't going to cut it today though. I think either a
fansink with no goop, but latched down, or perhaps a fansink with goop and
no latch would work long enough to POST. At least this should work with
parts with an IHS. Bare chips are going to be more difficult.

As far as goop goes, I'm with Del. Anything with salt is a very bad idea
(particularly with the bare-die chips). Perhaps some zinc-oxide sun block?

>> Likewise, if it's common for a single address line to burn
>> out in a chip that still posts, I need to consider it.
>
> Check the pinout. I consider any of the outside pins
> likely candidates for ESD.

I'd also check the outside pins to make sure they're still there. If
there is one with a zapped I/O, oh well! Refund the money. The customer
knows they're not buying new parts. There has to be some risk assumed at
that end too.

--
Keith
May 21, 2005 6:47:15 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 May 2005 01:44:40 -0600, A Jones wrote:

> On Fri, 20 May 2005 21:44:51 +0000, Robert Redelmeier wrote:
>
>> No fan is much easier than no paste. The fan is only needed after
>> the block heats up, and that takes minutes. For a temporary TIM,
>> I'd suggest Vaseline (microcrystalline petroleum wax) if there
>> are exposed electrical points on the CPU topside, or K-Y Jelly
>> (thickened isotonic saline) if there are no conductivity issues.
>> The water in the latter is an _excellent_ thermal conductor.
>
> So let's say I go with Vaseline. Then there's no controversy about
> whether the saline is a problem. Can I use Vaseline as a cheap
> substitute for thermal paste that's adequate for a post or
> even a boot to Windows?

As I said before, what about zinc-oxide sun-block? You should be able to
buy that stuff by the pound.

> If so, this is starting to sound like an attractive shortcut:

> 1. I coat the processor with Vaseline.
> 2. I rest a clean heatsink carefully on top of the processor so it
> rests flat, but I don't clamp it down.
> 3. I do a post or even a boot to Windows.
> 4. If it boots, I sell it. If the buyer has a problem, I refund
> or replace.
>
> Does anyone have a practical objection to this approach?

Maybe weight down the fansink, arranged such that it doesn't block the air
flow. Support the back of the board so it doesn't stress the board.
We had good luck supporting the back of the board with a sheet of
anti-static foam. The boards were just lined up on the bench with the
PSU's tucked out of the way.

I don't think I'd even bother booting Windows, unless you use it as an
advertising gimick; "Guaranteed to boot Windows". If it doesn't, refund
the money with no questions asked. Don't even ask for the onld one to be
returned.

--
Keith
Anonymous
a b à CPUs
May 21, 2005 10:25:08 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Del Cecchi <dcecchi.nospam@att.net> wrote:
> Nanogram? I don't think so.

Don't think about numbers -- calculate!

How much gel is left after wiping? Max 5um on the flat top
and 15um on the edges? That gives 800 nL or 800 ug. At 0.8%w
NaCl, that is 6400 ng. Call it low microgram if you wish.

Think if it a different way. You apply about one drop (50uL).
Good cleaning should remove 98+% leaving 1000 nL or 8000 ng.

> And look up Sodium and threshold instability.
> Goes back aways.

I did and got no good hits on Google. Can you be
more specific? Certainly sodium can contaminate printed
semiconductors, but it's got to get there. How is it going
to migrate through 1+mm resin or 0.5 mm hi purity silicon?

-- Robert
Anonymous
a b à CPUs
May 21, 2005 11:57:35 PM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

keith <krw@att.bizzzz> wrote:
> As I said before, what about zinc-oxide sun-block?
> You should be able to buy that stuff by the pound.

Zinc oxide sunblock is too good! Danm close to the RS stuff.
It is also somewhat hard to remove well.

-- Robert
Anonymous
a b à CPUs
May 22, 2005 12:48:18 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

keith wrote:
> On Sat, 21 May 2005 01:44:40 -0600, A Jones wrote:
>
>
>>On Fri, 20 May 2005 21:44:51 +0000, Robert Redelmeier wrote:
>>
>>
>>>No fan is much easier than no paste. The fan is only needed after
>>>the block heats up, and that takes minutes. For a temporary TIM,
>>>I'd suggest Vaseline (microcrystalline petroleum wax) if there
>>>are exposed electrical points on the CPU topside, or K-Y Jelly
>>>(thickened isotonic saline) if there are no conductivity issues.
>>>The water in the latter is an _excellent_ thermal conductor.
>>
>>So let's say I go with Vaseline. Then there's no controversy about
>>whether the saline is a problem. Can I use Vaseline as a cheap
>>substitute for thermal paste that's adequate for a post or
>>even a boot to Windows?
>
>
> As I said before, what about zinc-oxide sun-block? You should be able to
> buy that stuff by the pound.

Why not a flat-bottomed steel bottle full of liquid nitrogen ?

Set it on processor, test, lift it off. Repeat with next CPU.
You can|should insulate the walls of the bottle so that the
nitrogen lasts a little longer.

With something nice and cold like that a perfect fit between the
CPU & bottom of the bottle shouldn't be necessary for a simple
one or two minute test.


>
>
>>If so, this is starting to sound like an attractive shortcut:
>
>
>>1. I coat the processor with Vaseline.
>>2. I rest a clean heatsink carefully on top of the processor so it
>> rests flat, but I don't clamp it down.
>>3. I do a post or even a boot to Windows.
>>4. If it boots, I sell it. If the buyer has a problem, I refund
>> or replace.
>>
>>Does anyone have a practical objection to this approach?
>
>
> Maybe weight down the fansink, arranged such that it doesn't block the air
> flow. Support the back of the board so it doesn't stress the board.
> We had good luck supporting the back of the board with a sheet of
> anti-static foam. The boards were just lined up on the bench with the
> PSU's tucked out of the way.
>
> I don't think I'd even bother booting Windows, unless you use it as an
> advertising gimick; "Guaranteed to boot Windows". If it doesn't, refund
> the money with no questions asked. Don't even ask for the onld one to be
> returned.
>
Anonymous
a b à CPUs
May 22, 2005 2:19:41 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Bitstring <pan.2005.05.21.18.39.50.993377@att.bizzzz>, from the
wonderful person keith <krw@att.bizzzz> said
<snip>

> Perhaps some zinc-oxide sun block?

Why would you bother when you can get Zinc Oxide 'generic' thermal paste
in litre pots for a few shillings? I mean you really don't have to use
the latest Antarctic-Palladium-Ceramic-Version 6b. In fact is doesn't
make a degree difference anyway, if the HS is actually flat.

--
GSV Three Minds in a Can
Contact recommends the use of Firefox; SC recommends it at gunpoint.
Anonymous
a b à CPUs
May 22, 2005 2:31:37 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Rob Stow <rob.stow@shaw.ca> wrote:
> Why not a flat-bottomed steel bottle full of liquid nitrogen ?

Dry ice in iso propyl alcohol is easier to obtain and handle.

> With something nice and cold like that a perfect fit between
> the CPU & bottom of the bottle shouldn't be necessary for
> a simple one or two minute test.

The beaker will frost over, and if that frost is the right amount,
it will melt and act as thermal transfer medium. Water is actually
pretty good. Too much will make the chips wet.

-- Robert
May 22, 2005 2:46:57 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 May 2005 18:25:08 +0000, Robert Redelmeier wrote:

> Del Cecchi <dcecchi.nospam@att.net> wrote:
>> Nanogram? I don't think so.
>
> Don't think about numbers -- calculate!
>
> How much gel is left after wiping? Max 5um on the flat top
> and 15um on the edges? That gives 800 nL or 800 ug. At 0.8%w
> NaCl, that is 6400 ng. Call it low microgram if you wish.
>
> Think if it a different way. You apply about one drop (50uL).
> Good cleaning should remove 98+% leaving 1000 nL or 8000 ng.
>
>> And look up Sodium and threshold instability.
>> Goes back aways.
>
> I did and got no good hits on Google. Can you be
> more specific? Certainly sodium can contaminate printed
> semiconductors, but it's got to get there. How is it going
> to migrate through 1+mm resin or 0.5 mm hi purity silicon?

A couple of atoms in the wrong place is 'nuff. Sodium is nasty stuff, as
anyone living in the North can attest to.

--
Keith
May 22, 2005 2:48:51 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 May 2005 22:19:41 +0100, GSV Three Minds in a Can wrote:

> Bitstring <pan.2005.05.21.18.39.50.993377@att.bizzzz>, from the
> wonderful person keith <krw@att.bizzzz> said
> <snip>
>
>> Perhaps some zinc-oxide sun block?
>
> Why would you bother when you can get Zinc Oxide 'generic' thermal paste
> in litre pots for a few shillings? I mean you really don't have to use
> the latest Antarctic-Palladium-Ceramic-Version 6b. In fact is doesn't
> make a degree difference anyway, if the HS is actually flat.

It's really the same stuff. Sun-block is easier to find though. Look for
the lifeguards with the white noses. ;-)

--
Keith
May 22, 2005 2:53:35 AM

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 May 2005 20:48:18 +0000, Rob Stow wrote:

> keith wrote:
>> On Sat, 21 May 2005 01:44:40 -0600, A Jones wrote:
>>
>>
>>>On Fri, 20 May 2005 21:44:51 +0000, Robert Redelmeier wrote:
>>>
>>>
>>>>No fan is much easier than no paste. The fan is only needed after
>>>>the block heats up, and that takes minutes. For a temporary TIM,
>>>>I'd suggest Vaseline (microcrystalline petroleum wax) if there
>>>>are exposed electrical points on the CPU topside, or K-Y Jelly
>>>>(thickened isotonic saline) if there are no conductivity issues.
>>>>The water in the latter is an _excellent_ thermal conductor.
>>>
>>>So let's say I go with Vaseline. Then there's no controversy about
>>>whether the saline is a problem. Can I use Vaseline as a cheap
>>>substitute for thermal paste that's adequate for a post or
>>>even a boot to Windows?
>>
>>
>> As I said before, what about zinc-oxide sun-block? You should be able to
>> buy that stuff by the pound.
>
> Why not a flat-bottomed steel bottle full of liquid nitrogen ?

It is cheap stuff, but it's a little hard to handle for such things.
Besides, there is such a thing as *too* cold. Yes, Liquid Nitrogen is
often used in testing, but water is easier unless testing at the low
extremes (0C, for commercial) is needed. For these purposes air should
work fine though.

> Set it on processor, test, lift it off. Repeat with next CPU. You
> can|should insulate the walls of the bottle so that the nitrogen lasts a
> little longer.

Too cold could cause all sorts of problems.

> With something nice and cold like that a perfect fit between the CPU &
> bottom of the bottle shouldn't be necessary for a simple one or two
> minute test.

Exactly. Why go to this extreme though.

--
Keith
!