green pictures -> NEED dead CPUs

this is all about flatness
a bit of explanation: I bought a "Flatscope" which is an optical flat built into a reflex viewer with a mercury lamp and a green filter
- as such each visible fringe = 0.000010749" (~ 0.000273mm) and 'measurement' is made counting the fringes, or fractions, in terms of their deviation from linearity
(its not about how many fringes, its how curved they are; a bit oversimplified but that's the gist of it)

so I started looking at wbs, my present interest
(note that the surface must be reflective, more on this later; and that the images are severely pushed to enhance the contrast)
some examples - of my handicraft, no blame to the mfgrs here

the first wb bp I looked at, I was shocked (not my lapping)


a 'not good' of mine


here the die area can be seen towards the lower center


and one that is actually pretty good


too many images I’m told, have to split the post
to be continued . . . .

flatness, Part 2

then I took a look at the heat die, not too enthused so I re-lapped it

but found after a bunch of testing that there was no discernable difference

on to the BIG question: what does the top of a CPU look like ?
but I had none to ck, called JoeC and he sent me a dead Duron and a P3
but both had non-reflective surfaces, time to lap which I did using ONLY 1µ film (the idea being to polish, not flatten)
- a big chore; the green 'coating' on the Duron seems to be a silicon oxide somehow processed to yield that finish (anyone know ? - not think, eh - know ?)
- and the P3 was just as difficult, looks like gun bluing - but MUCH harder

the Duron

pretty flat really

and the real shocker, the P3

it has a point on it like a church steeple (which I do not believe is any accident)

what can be said about all this ?
nothing, a sample size of one, on different CPUs from different mfgrs is not a basis for anything other than idle speculation

but if I had more CPUs to look at . . . . .

AN OPEN REQUEST TO OCers: I need your dead, un-lapped of course, CPUs - those sold w/o heatspreaders

I'd like to do an article on this subject -> but I need to see something more that a couple to have any validity at all

corner cracks ok, I can inspect
my address is HERE
please contribute

be cool

Bill,

Can you suggest a link that would help in interpreting these images?

Tecumseh came up with this, hard to find useful stuff
(also donated some flats !!)

http://www.grahamoptical.com/interp.htm

be cool

Thank you.

Looks like something you could get a lot better feel for by playing with the tilt table.

I'm guessing the optical flat is fairly useless without a tilt table?

no, the fringes are caused by the 'air wedge'
- the number of fringes being a consequence of the wedge angle

since ideally the light and view perspective are both normal to the object face (as with a reflex viewer using a beam splitter), not so sure that a tilt table - with which I have no experience - does much other than vary the band density
- but it is the band curvature that is relevant, fewer bands enabling greater accuracy ?
or enabling computerized optical scanning/recognition ?

much I don't know about this

but I NEED CPUs

be cool

I think the rings that you are seeing is the so-called Newton's Rings. It's caused by light interference due to path differences (which is the air-wedge x2). If you want, i can find more detailed data on this - i'm also interested in how the rings relates to how flat the object is (all i remember is that it's related to radius of curvature )

PS - I did this as part of my course in University (but i've forgotten the details... )

go to newegg.com and look at their refurb section, then go to the dent and scratch section and search for cpu's.

They offer dead units for .25 plus shipping for display purposes. They must have a bunch of them since they offer a shipping deal for purchase of 20 units.

here is the link

eaglescouter
thanks for the link, but I think a P5 socket 7 may not reflect 'current' processes
(but I encountered an 'upgrade socket', new to me - perhaps I can salvage a couple of obsolete boxes I have)

STILL NEED A FEW DEAD CPUs fellows
gee, I'm getting boring

be cool

I've got a dead XP1600 I killed last week at the office. I'll send it to you next week.

cmcquistion
Thank You

be cool

EDIT: let me restate the purpose of this investigation
1) how flat are CPUs ?
2) is there a pattern to their 'non-flatness' ? (if any)
3) what does the CPU flatness imply wrt bp flatness ?

note that while I may have some curosity about making a CPU flatter than as shipped,
I would never recommend such - or do such to my own

I'd suggest linking to this in water cooling. Only occasionally do I glance through the first few posts in general cooling.

Those with riskier cooling setups may have more dead CPU's.

How large an optical flat is needed for looking at waterblock base flatness?

Would a 1" flat be too small to be useful?

Was it tricky holding the flat to the right orientation with respect to the DUT?

edit: BTW Bill needs dead CPU's.

in theory 1" would be sufficient, but you would have no understanding of the general topography

the "Flatscope" I have has a 3" sq flat, but all others I've seen are round

'holding it' is not an issue, you set it on the work, or vice versa
but the light orientation is a 'problem' as off-axis introduces an error
-> but you need a monochromatic light, helium or mercury with a filter

and yes, I STILL NEED DEAD CPUs

be cool

i have a few here~
PM me

Is it just me is anyone else unable to view any of those images? Anyway, talking about flatness, I was messing with my camera a while back (photographing the unlocking process) and took these pictures of an Palomino core :


(Click for a larger image)

Note how grainy the surface looks. Interesting no?

the images are on pwebtech, got to be the worst hosting co in the world - but cheap
may be timing out ? they are in NJ, lots of DOS stuff apparently

yea, the surface is 'bright', but highly angular
this is what has to be lapped flat enough to be somewhat reflective
- without of course imposing a brand new topography

be cool

very interesting indeed. I hope you follow this, i'm interested in the results. I beleive i have 3 or so dead AMD's to send (durons and xp's) PM me after this weekend if i don't contact you (have to get to the cpu's, they are at my house and not my dorm).

and a big Thank You to Thomas Lewis of Gonzales for 3 dead CPUs
(he cared enough to send his very best)

-> STILL NEED DEAD CPUs fellows

be cool

i have a couple uncapped k6-2's i believe they're 333 and 350s pm me if you're interested