Need to know P4 (478) pin assignments of CPU

[Vigilante]

Hey fellas, been doing some googling to no avail. Does anybody know a site or place that has pin assignments of CPUs?
Or more specifically, the P4 mentioned in the title?

It's funny, a customer brought in a PC (HP) that doesn't boot. I was doing a diag and eventually took the CPU out, to my surprise there were bent pins all over the place!
I did my best to straiten them out, some were flat down on the chip, it wasn't easy. But there is one that just snapped off. However, when I put it back together, it worked! Even without the pin. So I'm trying to find out what pin that is and what it does.

thanks.

 

[Didou]

From the horse's mouth.

http://www.intel.com/design/pentium4/datashts/24988703.pdf (starting at page 53).

 

[Vigilante]

Sure, why would Intel have those specs on their own CPU? If Google doesn't find it, it doesn't exist! lol

Well based on their chart (page 63). My missing pin could be C1, or AD26, or A23.
2 are inputs, 1 is input/output. hmmm

thx

 

[Jaquio]

Its amazing how that CPU works having it pins bended... AND EVEN MISSING ONE!!!...
your one lucky brother... LOL

 

[swker98]

what i wannna know is how those pins got bent in the first place

 

[mossimoboy]

Probably his customer just jammed it in and slapped the HSF on.
lol.. Just my imagination running wild.

 

[Jaquio]

Yeah... thats what happend... he didnt realize there was a way to put the CPU...

 

[swker98]

this kind of reminds me of this :haha: :haha:

 

[Vigilante]

haha, ya just a "bit" to much I think.

Well just to stir the pot some more. This is an HP only about a year and half old. Nobody had been in the machine except I think they may have replaced a CD-ROM. When I took the heatsink off, the CPU just came right out with it, with almost zero force, stuck to the heatsink. That doesn't explain how a single pin could get squished down, while the pins around it are strait.

Very odd indeed.

 

[Nodsu]

Could be a "refurbished" machine, put together from used parts.

The TAP signals are used only for testing the CPU in the factory and the thing will run fine in a motherboard without those pins.

 

[Vigilante]

Naw, supposedly it is a new HP, bought from Costco or Best Buy. But who really knows these things? They probably got into it and don't want to confess. Can't blame them really.

 

[MetalX]

haha, ya just a "bit" to much I think.

Well just to stir the pot some more. This is an HP only about a year and half old. Nobody had been in the machine except I think they may have replaced a CD-ROM. When I took the heatsink off, the CPU just came right out with it, with almost zero force, stuck to the heatsink. That doesn't explain how a single pin could get squished down, while the pins around it are strait.

Very odd indeed.

When i bought my computer, it was supposedly new but when i replaced the mobo, the processor looked pretty beat up and was dented. Also my proc was stuck to the heatsink as well and i had to pry it off. Funnily enough, my Pentium 4 2.26 ghz which came with the machine had 480 pins. The two that are supposed to be empty were filled. So i took a risk and figured out which ones werent supposed to be there and bent them untill they came off... now it works fine except that it is not overclocking very well considering it IS a northwood. . . only 2.26 to 2.72

 

[Vigilante]

Ok that's gotta be the weirdest story.

So now the OEMs are tricking the end users to get those prices down eh?

 

[Nodsu]

It's not "now".. It has always been that way.

Why would anyone throw away all the expensive stuff they get back via RMA? Most of the parts are in perfect condition or can be repaired with minimal cost - just label it as OEM and ship away..

 

[1luckydude]

Pinpoint PINS using chart from Intel-THE TWO MISSING PINS OF THE CPU ARE A1 and A2

Well that first reply is really helpful. It saved me here, months later after your posting in Jan of 2006. I am in May of 2006. But at first I was confised by the directions given as follows:

Didou01-11-2006, 06:50 PM
From the horse's mouth.

http://www.intel.com/design/pentium4/datashts/24988703.pdf (starting at page 53).

I noticed someone else was too, so here is my belated two cents worth. you need to look at the graphic pin layout chart on PAGE 52 !!!!! lol It looks like a checkerboard square. But note that the chart on page 52 does not reveal the little key we alll go by when inserting the p4 cpu, at least not visually. But it does verbally. The trick is to note that the chart is saying is seen as viewed from the "top of the package". What that means is that if you look on page 51 <----- [important] you see how the little dot tells you the right placement of the two missing pins used for the KEY. So ok, to view the chart on page 52 the right way just FLIP the CPU over horizontally, from left to right. Now you will be able to make sense of the number charts, because THE TWO MISSING PINS OF THE CPU ARE A1 and A2. Thats why they are not listed, because they are the key. To be even more clear, once you flip the CPU horizonally from the view on page 51 should now be at your bottom right, just like on the chart on page 51 they are on your bottom left where the little arrow is located. I hope this helps. The 2d Matrix mark was not in the same place on my CPU, but the dot and the arrow were. Keep a clear focus and make no mistake about it.

In my case I was able to see that my missing pin was the 1st on a 3d row, but I could not at first figure out which one. (My story was like that of vigilante's, and like him I googled but thats how I found you guys, thanks for being here -- I am sooooo glad I had saved that old cpu for when I needed it for a motherboard. I was trying to rescue a customer computer with another motherboard but his processor was a 533 mhz and the replacement motherboard needed a 400 mhz processor, fortunately I had that old one with a pin missing! And to think I almost threw it away. Anyway, it turned out to be pin AD26, a TAP pin that I learned here was not essential). Thanks to all, and to Didou for posting that link to the Intel PDF file. Suggestion: once you review the PDF file save a copy for future use.

 

[1luckydude]

How to remove a glued CPU from heat sink when lever not accessible

OK, one more thing, fellas. In my case I had ripped the pin from the CPU because I had used that stupid pink paste that comes in little squares. I thought it would be a convenient thing to use when I bought it at CompUSA. But we all now know (or be forewarned) that is turns into a solid glue that keeps you from removing the heatsink without ripping the CPU pins, and you cannot reach the lever because it is under the CPU. Well here is the simple solution.

The paste turns into a solid glue when cold, but when hot it is softer. By the time we are working on a computer it is usually cold, and sometimes it cannot be powered on or we prefer no to power it on. So do this:

TAKE A BLOW DRYER, and aim it with a smile at the heat sink long enough to make it heat up as if the computer was running nice and hot on a summer day in a room without AC. When the metal has heated up enough it should have made the paste soft enough to pull the CPU off. After you get the heatsink off the CPU, you lucky dog, you can then move the lever and lovingly remove that CPU. Now take a nice razor or something like that and shave off that ugly paste, being careful to not scrape off the other info from the back of the CPU. I did not have any solvent or I might have tried just wiping it off, but it is a pretty though little gummy thing, so I used a razor from a sheetrock cutter, like many use to cut boxes. Point is, just remove the darn thing. Then replace it with regular heat paste if you can, to do good work. None of us need to lose a $100 bucks having to replace a cpu over a $1 piece of paste! Good luck to all facing a stuck heatsink or heat sink that will not come off a CPU (I insert this last line as a search phrase). Thanks.